Talk:12-hour clock/Archive 2

Archive 1

Archive 2

Archive 3

Abbreviations

The section titled "Abbreviations" has no cites and I couldn't find any mention of the PD an MD in Albanian on a Yahoo! search other than Wikipedia and its forks and mirrors. Zginder 00:46, 29 August 2007 (UTC)

Yeah, besides being cute (I'd love to call 8am "eight-pi-mu" and 3pm "three-mu-mu"), this section is redundant, unsourced, and completely unnecessary. I strongly suggest deletion. -- Tkgd2007 (talk) 22:34, 10 April 2008 (UTC)

"...one must fall back on one's cultural literacy to disambiguate". Besides not passing the laugh test, it is an overstatement of the situation. It is taking something rather elementary and making it appear difficult. JackOL31 (talk) 15:32, 1 January 2010 (UTC)

"The use of a.m. ... can be confusing because am is an English word, AM ...amplitude modulation and A.M. ... anno mundi, in the year of the world, and for Master of Arts". This is an example of excessive criticism. Context clues can not be ignored and we cannot frame this from the perspective of a clueless person. All abbreviations are typically used within a context where the meaning is clear. This article uses BC and AD, however I don't see any criticism that those might be confused with - British Columbia, Book Club, Birth Control, Boston College, Bar Code, Before Christmas, Bankruptcy Court, Board Certified, Birth Certificate and Birth Control -or- Assistant Director, Associate Director, Active Duty, Attention Deficit, Associate Degree, Air Defense, and Assistant Deputy. Also, the mention of the recommendation for a space between the time and a.m./p.m. is sufficient. There is no proof that it is widely ignored (and violated is too strong a word for a stylebook convention). Lastly, combined similar concepts into a single paragraph. JackOL31 (talk) 02:43, 5 January 2010 (UTC)

History and use

Modified the last paragraph to include the inner ring values of 00 & 24 for the 12. Improved some of the wording. Also deleted the redlink to Comparison of the 12-hour and 24-hour clocks, which was deleted in October. JackOL31 (talk) 01:52, 19 December 2009 (UTC)

In the "Use by country" subsection, I revised the wording to present a more NPoV. The use of the term "unambiguously" is not necessary. It is sufficent to indicate the alternative terms to a.m./p.m. where it is not used or known. JackOL31 (talk) 03:47, 5 January 2010 (UTC)

The above seemed like a small change, changing wording slightly for NPoV. Otherwise, I would have posted chg in discussion and asked for comment. Once change is made, please discuss if differing view. I don't expect my good faith edits to be backed out. Please discuss why a more neutral PoV is not the proper wording. 173.88.207.233 (talk) 05:24, 5 January 2010 (UTC)

Oops, I did not login above. JackOL31 (talk) 05:27, 5 January 2010 (UTC)

Your anonymous modification made a correct reflection of reality rather inaccurate. Therefore I had no doubt reverting it on sight. Here the explanation:

• In many ... countries the 12-hour clock is commonly used ...
  • sets the reader on the wrong footing; it may be used, but mostly in informal statements only
• In some instances, the terms a.m. and p.m. are not used or known.
  • outside the English speaking countries they are almost never used and often unknown; circumlocution is the only way of disambiguation.

These points were very clearly stated before your change. I do not see any POV in all this. They are statements of fact, not opinion. −Woodstone (talk) 14:15, 5 January 2010 (UTC)

I always try to bear in mind that even anonymous contributors are allowed full privileges when updating. Unless there is vandalism or gross misinformation, there is nothing to lose by starting a discussion and reaching an understanding prior to reversing out someone else's time and effort.

On another note, I can agree with your revisions. I propose the following:

In many European countries and Western countries, the 12-hour clock is commonly used in informal speech with descriptive phrases such as in the morning, in the afternoon, in the evening, and at night.[citation needed] Outside of English speaking countries, the terms a.m. and p.m. are rarely used and often unknown.

Non-neutral wording does not necessarily imply opinion, statement tone and innuendo also play a part. Wikipedia calls it a disinterested tone, I think of it more as a matter-of-fact tone. The earlier changes move toward that tone and also improve the concept flow.

I don't believe I can agree with your circumlocution assertion. I lean more towards - say it once, say it precisely, and say it concisely. JackOL31 (talk) 04:11, 6 January 2010 (UTC)

Can accept proposed new wording. Circumlocution was meant to apply to expressing the abbreviation a.m. by a phrase like "in the morning". In non-English Europe that is practically the only way the 12 hour clock is disambiguated every time it is required. −Woodstone (talk) 04:34, 6 January 2010 (UTC)

Changes made with one small exception, used "seldom" in place of "rarely". Seldom seemed more appropriate. This info still needs a citation though. Regarding your last statement, I perceive things differently than you. One can say 6:30 p.m., 18:30, or 6:30 in the evening. There is no aspect of ambiguity requiring disambiguation. It is flat out unambiguous. The interesting aspect of the 12-hour system is that one could say, for example, "I look forward to seeing you tomorrow at 6:30" and 99 44/100% of the time the correct meaning is still understood. For the other 56/100% of the time, you simply don't abbreviate. I've been saying that since '93. (Eh, that would be 1993 - not 1893, but you already knew that!) JackOL31 (talk) 01:51, 7 January 2010 (UTC)

Features of the 12-hour clock

Made a couple of small improvements/corrections. Changed "which almost all have just 12 hours" to "most of which display only 12 hours". Also, modified the reference to chiming the hour to striking the hour. A clock may chime on the hour, typically 4 times, but it strikes the count of the hour. They are two separate concepts. A few Wiki articles have this wrong, but I will take that up on their respective discussion pages. Removed the overstatement "requiring an understanding of it". First, there is no need for anyone to understand it (other than the clock manufacturer) for a clock to strike three times at 3 o'clock. Secondly, these are the same people who use "in the morning", "in the afternoon", and "in the evening". If you're around a 12-hour striking clock, you're know enough to get by. There needs to be some evidence of people hearing striking clocks and having difficulty understanding them to suggest "a required understanding". Everything requires an understanding in one way or another. JackOL31 (talk) 04:18, 7 January 2010 (UTC)

Section: Criticism and practical problems

This article states that one of the problems with this convention is that "It is not immediately clear on an analogue clock whether a time is a.m. or p.m." Calling 6:00 p.m. "1800" won't solve this problem, either. (The only reason I noticed this is that I've been working on a 24-hour analogue clock. Everybody seems to like it so far except for little kids).

And one more thing: Is it really more complicated to implement in software and digital electronics? How much code does it take to convert 1300 to 0000 to pm? That's like saying it's more difficult to eat a 45 oz steak as opposed to a 40 oz steak. Technically, yea. But no one's gonna notice. —Preceding unsigned comment added by Antigrandiose (talk • contribs) 19:41, 31 March 2010 (UTC)

The use of twelve instead of zero

I recall that the use of 12 instead of 0 in clocks was attributed to the non-existence of the number 0 until the 10th century, though I can't seem to find a source to evidence this, does anyone here know more about this? —Preceding unsigned comment added by 115.64.132.151 (talk) 14:03, 10 August 2010 (UTC)

Is it exactly 24 hrs between midnight to midnight, every day of the year or does it vary and averages to 24 hrs ?

It just came to my mind. This may be vague, and may not be a question though, in the universal context is our 24 hrs a 24 hrs exactly the same everyday from midnight to midnight. or does it vary each day and averages to 24 hrs every year i.e on full revolution. Chandrakantpushkar (talk) 09:22, 21 September 2010 (UTC)

It depends on what you mean. In the sense of 12-hour clock every day is precisely 86400 seconds, except once in many months, when a leap second is added, and that day is 86401 seconds. However if you mean the time between the Sun being at its highest point on successive days, it varies quite a bit, somewhere in the order of plus or minus 20 seconds. Over months it adds up to plus or minus 15 minutes. See for a detailed explanation Equation of time. −Woodstone (talk) 16:15, 21 September 2010 (UTC)

POV

Original edit summary [1] "It's been my experience traveling the globe that everyone uses the 24 hour system with the exception of the U.S. Look at the website for airlines in any country to see what time system is used."

As you can see "My experience" is POV (where's the citation?), and airlines typically ALWAYS use the 24 hour clock around the world, just as trains do, and other forms of public transport! That doesn't say anything about what people use on a day to day basis, or even other businesses apart from transportation. Strange how the edit was by "MetricMike" who "wish[es] the US would get on with the conversion to the much simpler and more rational System International". Obviously biased editing. 91.85.177.45 (talk) 07:01, 26 September 2010 (UTC)

Let me Enlighten You

It appears from this article as well as the 24 hour clock article, which I will cc this comment to, that most if not all editors on this subject have missed the concept of a clock completely. Though, it is understandable to me because I myself did not make this realization until recently.

It is quite amazing to see that the creators of this ancient time measurement system seemed to understand this deep fundamental concept and was never questioned. While now all these smart anonymous editors don't even sense the concept rushing past them due to their weak reasoning.

Now that I am done being rude caused by the confident yet wrong content of this article let me prove my worth, though I will warn you I am not good at transcribing my thoughts to natural language but I will try my best so please bare with me.

The first thing to understand is that there is no such thing as Time = zero. When Time = zero it means you are dead. It does not exist because time only exists to you because you are alive to perceive it. In other words, the moment in time is a function of your unitary perception of all the preceding time before that moment such that your unit of perception is to the power of e.

Heh, let me try and explain that again. T = f(x):=e^x So when you born, that absolute infinitesimally tiny moment when you perceive life. That is one unit of time, as soon as you continue to live for another one of those units of time, that is now the second unit of time. http://en.wikipedia.org/wiki/E_(mathematical_constant) see this article for help understanding what I mean. Time would be the Y in the graph. As soon as you first perceive life, when x=0 time is 1. This is why there is no year zero. This is why there is not time 0:00 on a 12 hour clock. This is why I think a 24 hour clock is strange. Having time go from 23:59 to 24:00 then to 0:00 then to 0:01 makes no sense unless you share 1 second between 24:00 and 0:00.

There is a comment somewhere that says it is ambiguous as to whether midnight is the start or end of the day, yeah, no shit. You tell me what it is! A day is not an isolated universe of time, it is part of a continuous fabric of time that has not start or end. The end of the day is the start of the next day, there is never a moment when Time = zero as soon as the big bang happened. Time was 1 if you think that there must be a fraction of a moment before that first 1 then whatever fraction you are imagining would be the unit of time so that would be 1. As soon as there is existence time has already been created and it increasing.

The present is an infinitely small moment of time that is imperceivable, as soon as you notice it, it has already passed. You exist physically in the present but your mind exists by watching time fly towards you and then past you into the past as it gets locked into the memory of the universe and irrevocably stamps it's impact on all future events.

This can be intuitively seen and understood by every person. We all know that each year of our childhood felt very long. And as you get older every year seems to go by so much faster! This concept shows up in pop culture with sayings from kids like, "Are we there yet?" and old people such as, "It was just like yesterday."

The reason this is is because say you live for 1 year. Then you live 1 more year. You just doubled your life! As far as you are concerned you just lived for forever! Twice! Which becomes the new forever. And as you become 50 once you live one more year that is no longer as large an amount of time. It is only 1/50th what it used to be.

So the reason 12:00 the one that happens during the daylight where you are. Is called 12:00 pm is because as soon as 11:59 ticks one unit to 12:00 there is units less than a second we cannot comprehend that have already begun counting up. Once they reach 1 second it becomes 12:01 pm which is clearly the afternoon. So since some people like to clarify 12:00 when it is sunny with 12:01pm and not just 12:00pm, just think it is really 12:00:00:00:00:00:00:01 the moment it flips from 11:59 am.

That is why there is no 0:00. And I would love to hear from some electronics engineer explain how a 24 hour clock can display both 24:00 and 0:00. I did not realize time did not exist for 1 second everyday. I just am not sure if that second is at the 24th hour or the zeroth hour. Heh, zeroth hour, funny people and their made up symbolic lies.

I like how people think that when zero was realized to be a number they think that means it can exist. I'm sorry, zero does not exist. That is what zero is, none existence. It is what is inside that little circle we use to show it's concept. If you have 4 apples, and you give away 4 apples you don't walk around with a special magical apple known as your zeroth apple. You walk around empty handed saying, "I have zero apples!"

That is why the month does not start on day zero and then move to day 1. The month starts on 12:00am actually. Which is also the end of last month in our macro world. Maybe some electrons get to tunnel into that zeroth second and freeze in time for who knows how long then popup somewhere else randomly. But that's the great thing about the universe! It's made up of real existence held together by irrational imaginary chaos.

Maybe that's where my mind lives, I hope you can join me there too and not just try to argue unsuccessfully against me. Because I would love to hear a justification on how, "The rollover from 12 to 1 happens an hour later than the change between a.m. and p.m." this sentence is even remotely disadvantageous.

I forgot to sign, that would have been a shame, eh? Rukaribe (talk) 12:09, 29 October 2010 (UTC)

Updates and active discussion here. Rukaribe (talk) 02:59, 7 December 2010 (UTC)

New day time in Judaism / Seventh Day Adventists

I've noticed that in Judaism and Seventh Day-Adventist faiths they celebrate the next day at sunset (as opposed to arbitrary time of 12:00am or 00:00). Is there any specific term for their start of the next day at Sundown? CaribDigita (talk) 16:35, 27 December 2010‎ (UTC)

Informal speech and rounding off

First, let me state my background, I am an Englishman living in America. I agree with the observation that the phrase "half five" (meaning 5:30) is not understood in America (and is often met with the question "is that 4:30 or 5:30?"). I live in the midwest (Chicago) and I've never heard "half five" used to actually mean 4:30 as this section goes on to suggest, though if it's use is limited to the German communities, I could have missed it.

I didn't hear 5:45 referred to as "a quarter of six" until I moved to America (and to this day, I never remember if it means "a quarter TO six" or "a quarter PAST six"), so I'm guessing that is just a US phrase and not a UK phrase.

Any thoughts? Robman94 (talk) 22:12, 24 January 2011 (UTC)

Confusion at noon and midnight - Table - Digital 24-hour clock displays

Resolved

 – As per sub-discussion in #Confusion at noon and midnight - table - midnight, end of day, for clocks, I've removed the row with the digital clock showing 24:00 at midnight Mitch Ames (talk) 10:08, 12 February 2011 (UTC)

Although most 24-hour digital show midnight as 00:00, according to the last paragraph of 24-hour_clock#Midnight_00:00_and_24:00, "the digital clocks of at least one European manufacturer of kitchen appliances show 24:00 for midnight ... an example being Bosch Siemens microwaves". I propose that the table in the "Confusion at noon and midnight" section should include a row for this, eg:

Style	Midnight start of day	Noon	Midnight end of day
Most digital 24-hour clock displays	00:00	12:00	—
Some digital 24-hour clock displays	—	12:00	24:00

The above example follows the convention of the existing table. As per separate discussions above (Talk:12-hour_clock#.22clock_system.22_table_-_midnight_and_noon, Talk:12-hour_clock#Confusion_at_noon_and_midnight_-_table_-_midnight.2C_end_of_day.2C_for_clocks), I would prefer to see:

Style	Midnight start of day	Noon	Midnight end of day
Most digital 24-hour clock displays	00:00	12:00	00:00 (start of next day)
Some digital 24-hour clock displays	24:00 (end of previous day)	12:00	24:00

Forget second para and table in this section. Better to keep the two issues separate. See Talk:12-hour_clock#Clarification_of_what_this_section_is_about below. Mitch Ames (talk) 12:14, 7 February 2011 (UTC)

Mitch Ames (talk) 03:53, 5 February 2011 (UTC)

The midnight at the end of a day cannot be referred to as the start of the next day. It must be either defined as a separate different notation or it must be undefined. A digital clock can only practically use one notation for any particular smallest precision unit (SPU), such as hour, minute, second. By their nature a digital clock has a SPU (as it is a count of periodic events). The most commonly used convention for time at least in the western world has two interpretations. Interpretation 1 is to display the last SPU completed. This convention is also used long intervals of time; e.g. something that is one year and 364 days old is said to be "one year old" it is not said to be "two years old". The second interpretation is that if your determine or display a smaller SPU the previously known digits do not change. In other world, time is always rounded down. This is used for dates. Stating what year it is does not change if your also state the month. Now a decision has to be made when these two interpretations of the convention disagree. The first SPU after midnight is interpreted by interpretation 1 as the completed day; e.g., 24, 24:00, and 24:00:00 in ISO 8601 and as 12:00 p.m. in some conventions of the 12-hour clock. By the second interpretation, which most people seem to use, the time is displayed as zero completed SPUs in the new day. By this convention, midnight is displayed as 0, 00, 00:00, 00:00:00 in the 24 hour clock or as 12:00 a.m. in some conventions of the 12-hour clock. Therefore, your suggested edits are not profitable for the edification of our readers in my opinion, as only one interpretation is used at a time. Zginder 2011-02-06T06:27Z (UTC)

Could you clarify please: are you opposing:

• the addition of the row "Some digital 24-hour clock displays" (ie the changes in my first table above)
• the replacement of a dash with a numeric value for end of day (most clocks) or start of day (some clocks)
• both of the above

I intend to press my case here (in a similar manner to per separate discussions above Talk:12-hour_clock#.22clock_system.22_table_-_midnight_and_noon, Talk:12-hour_clock#Confusion_at_noon_and_midnight_-_table_-_midnight.2C_end_of_day.2C_for_clocks), but I just want to check which points I need to argue. Mitch Ames (talk) 09:54, 6 February 2011 (UTC)

Whatever you write, please consider that while the instant 24:00 may well be described as the end of the previous day, a time interval after midnight in which the display shows 24:... cannot. How long does it show 24:... anyway? If it displays the seconds, I suppose most people would expect e.g. 3:12:47 to be displayed for a second beginning 3:12:47.00 and ending shortly after 3:12:47.99, i.e., we'd NOT expect common 4/5 rounding. Then, does it go from 24:00:00 to 0:00:01, from 24:00:59 to 0:01:00, or does it go all the way to 24:59:59 before changing to 1:00:00?--Nø (talk) 15:01, 6 February 2011 (UTC)

In the absence of any feedback on the matter, I've added the row "Some digital 24-hour clock displays" showing 24:00 at midnight end of day. Mitch Ames (talk) 12:23, 8 February 2011 (UTC)

It's Either Or in either case

An actual 24 hour clock is going to display either 00:00:00 at midnight or 24:00:00 at midnight but NOT both simultaneously. It is in this respect subject to the same limitation as a 12 hour clock, which could not display both 12:00:00 and 00:00:00 at the same time, were the zero hundred hours time conventional with 12 hour clocks.

Going on about the fact that one can, in speech or writing, designate the end of a twenty four hour period as 24:00:00 or its beginning as 00:00:00 is a matter of 24 hour notation, not of 12 hour clocks. The discussion is outside the scope of this article, and exists only because of the implicit assumption that 24 hour notation is superior. Having this here is like having a chart on the superior genetic health of interracial children in an article on arranged marriages. The notion, however compelling, is a POV, and not an appropriate reason for having this implied debate here.

μηδείς (talk) 15:54, 6 February 2011 (UTC)

"... the implicit assumption that 24 hour notation is superior ..."

Perhaps it's not necessarily that 24-hour notation is superior, but that ISO 8601 - which uses the 24-hour notation - gives us a well-defined standard reference for comparison. Mitch Ames (talk) 10:57, 7 February 2011 (UTC)

Also, as stated above, this article is about the 12-hour clock, not a 12-hour clock. It is about the 12-hour clock system, not just physical 12-hour clocks. The concept encompasses both what is denoted in writing to convey times, as well as what clocks or other time displays will show. −Woodstone (talk) 15:02, 7 February 2011 (UTC)

The fact remains that no clock actually displays both 00:00:00 and 24:00:00. It is either or. And if your response is that we are talking notation and not physical clocks then a 12 hour system could just as easily use 00:00:00 to indicate the end of the shift as opposed to the beginning. Again, the issue here is that the matter of the superiority of the 24 hour notation is unsourced POV which falls outside the scope of the article. μηδείς (talk) 17:51, 7 February 2011 (UTC)

The article is about the system, encompassing both physical clocks and clock time notations. And in agreement with you I quote myself from section 12 above: since midnight at end of day is the same instant as midnight at begin of the next day, a physical digital clock cannot display both. It has to make a choice.

The 12-hour clock also makes that choice for notation. So a contract, say for an insurance, might specify validity from 1 February 2011 at 0:00 a.m. till 1 March 2011 at 0:00 a.m. The article just compares such a notation without judgement to the international standard that could alternatively specify from 2011-02-01 at 00:00 till 2011-02-28 at 24:00. The former has the same time in a different month, the latter has a different time in the same month.

−09:20, 8 February 2011 (UTC)

Any chance of continuing the discussion in Talk:12-hour_clock#Confusion_at_noon_and_midnight_-_table_-_midnight.2C_end_of_day.2C_for_clocks above. In particular, Woodstone could you address my numbered questions, as I think it will help resolve the problem. (Likewise Talk:12-hour_clock#.22clock_system.22_table_-_midnight_and_noon.) Mitch Ames (talk) 11:28, 8 February 2011 (UTC)

Clarification of what this section is about

It might help the discussion if we limit this section "Confusion at noon and midnight - Table - Digital 24-hour clock displays" to whether or not we should add a row for "Some digital 24-hour clock displays" with 24:00 at end of day - ie my first paragraph and table.

The matter of whether "digital ... clock display" should include a value in both midnight columns (2nd para and table) belongs in Talk:12-hour_clock#Confusion_at_noon_and_midnight_-_table_-_midnight.2C_end_of_day.2C_for_clocks above. Mitch Ames (talk) 10:15, 7 February 2011 (UTC)

Reference to ISO 8601

In the table in the "Confusion at noon and midnight" section I've changed the row from "Written 24-hour clock, ISO 8601" to just "ISO 8601". The standard does not use the term "clock" at all, except to mention in its definition of standard time of day that "Standard time of day is called 'clock time' in IEC 60050-111". The table has a separate row for "Digital 24-hour clock" (ie a physical clock) and I think it best to avoid conflating the two. Mitch Ames (talk) 09:41, 13 February 2011 (UTC)

ISO 8601 is only a minority of the use of 24:00. That designation is quite common without adoption of ISO. So "written 24-h time" should stay. −Woodstone (talk) 13:30, 13 February 2011 (UTC)

I thought it best to not use the word "clock" in the ISO 8601 row, else some readers might think that some actual digital clocks can display both 00:00 and 24:00 - which we know they can't. "24-hour time" is perhaps too ambiguous, because it may imply (to some readers) "24-hour clocks". I suggest we should explicitly list the other (than 8601) uses of 00:00/24:00 - rail timetables, legal contracts etc - eg:

Style	Midnight start of day	Noon	Midnight end of day
ISO 8601, Bus/train timetables, Legal contracts	00:00	12:00	24:00

This covers the other uses even if they don't use 8601, and is clear and unambiguous. Mitch Ames (talk) 13:52, 13 February 2011 (UTC)

That covers only some of the uses and it omits to specify that it applies to usage in a 24-hour style. Could we make it "written time in 24-hour style". −Woodstone (talk) 14:15, 13 February 2011 (UTC)

The problem with "24-hour style" is that it is too broad. Not everyone who writes the time in "24-hour" format will use 24:00. Also "24-hour style" is ill-defined and potentially misleading. Trying to define "24-hour style" as something separate to what a 24-hr clock displays is just going to confuse people. Ask a few people if their 24-hour clocks use "24-hour style" - most of them will probably say yes. It is better to list a few examples that are correct, than to make a broad statement that is not always correct. Remember that we only need to give some examples - and add "etc" to the end of the row name - not list every possibility. If we were required to list every possible usage in that row, we'd also be obliged to list every style guide, in every country, that didn't follow 8601 - because the current table only covers some style guides. Mitch Ames (talk) 11:04, 14 February 2011 (UTC)

(moved up)The only way to denote midnight at the end of the day succinctly is 24:00 (the only alternative being a circumscription). So I do not see an issue of putting 24:00 in a row with header "written 24-hour clock" (written as opposed to displayed real time). −Woodstone (talk) 13:33, 14 February 2011 (UTC)

I don't understand what you're trying to say here. Which if any specific part of my post of 11:04, 14 February 2011 (UTC) do you agree or disagree with? Do you agree with splitting ISO 8601 into a separate row, or disagree, or don't care? Could you include a table (relevant rows only) showing what you propose, as I have done. Mitch Ames (talk) 13:56, 14 February 2011 (UTC)

The table should have:

• a row for a "digital 24-hour clock" (nothing in end-of-day)
• a row for something like "written time in 24-hour clock" (the latter includes ISO 8601), with 24:00 for "end-of-day". No need for examples of usage. Whenever end-of-day is used, it can only be 24:00.

The difference between the rows is not ISO vs time-table/contract/etc, but between real-time vs written. The question is how to name this row precisely. −Woodstone (talk) 14:17, 14 February 2011 (UTC)

I don't think that a different row/style for "what a digital 24-hr clock shows" vs "written down" is helpful. What if I'm simply writing down the time that I read of my clock? Mitch Ames (talk) 12:14, 15 February 2011 (UTC)

Given than ISO 8601 is specific and well-defined, whereas "Bus/train timetables, Legal contracts, etc" is incomplete and not so specific, there may be merit in splitting the current row thus:

Style	Midnight start of day	Noon	Midnight end of day
ISO 8601, reduced accuracy, extended format	00:00	12:00	24:00
Some bus/train timetables, some legal contracts, etc	00:00	12:00	24:00

("Reduced accuracy, extended format" is to distinguish from "complete representation, basic format", which would be hhmmss, ie no colons and show the seconds.)

This removes any implication that timetables, contracts etc necessarily follow ISO 8601. It does duplicate the contents of the rightmost columns, but I don't see that as a big problem - certainly it doesn't affect the ability to find information in the table. It also means that we can leave ISO 8601 out of any further discussions of what to call the other row. 8601 is well defined, so there should be little or no disagreement about the contents of that row. Mitch Ames (talk) 11:20, 14 February 2011 (UTC)

I propose that we suspend this discussion about ISO 8601 vs "other" until we have resolved #Confusion_at_noon_and_midnight_-_table_-_midnight.2C_end_of_day.2C_for_clocks. Until we agree on what the point of the table is, there's little use in discussing individual rows. Mitch Ames (talk) 12:17, 15 February 2011 (UTC)

Logic

The sentence in the article "midnight could logically be called ..."12 a.m." (12 ante meridiem, 12 hours before the following noon)" is rubbish, because all the other hours are hours after the previous one. So logically, after 11 p.m. the next would be 12 p.m., which would be the same time as 0 a.m. But, of course, logic and usage do not always go well together.--Marschner (talk) 18:44, 27 February 2011 (UTC)

I loved your point of logic as that drives me crazy. But the Jin of Computer Typing seems to have done its magic. At the above "same time as 0 a.m." could that have read "same time as 00:00." I'm not sure, if wrong sorry for the post Bio watcher (talk) 14:53, 2 May 2011 (UTC)

"clock system" table, noon = 12:00 m

Jc3s5h recently changed the noon entry in the "clock system" table from "12:00 p.m" to "12:00 m." because "m stands for meridiem which is noon; noon is neither before or after itself". I don't agree with this because:

• The use of "m" by itself is rare or non-existent on clocks, which is the topic of this article. (Although perhaps the article should be renamed to "... clock designation" or similar, because the article covers not just physical clocks.)
• The asterisk next to the entry in this table refers the reader to Confusion at noon and midnight which lists several designations, with no indication that "m" is preferable. Perhaps we should list all of them in the "clock system table".

After a previous long and tedious discussion about the table (#"clock system" table - midnight and noon) - which I'm not sure actually achieved anything - I'm not sure I want to go through it all again! However, I still think that any discussion about the contents of the table is meaningless until we agree on the purpose of the table, ie what it is intended to list. A more descriptive table heading and/or some explicit descriptive text would help. Mitch Ames (talk) 04:04, 3 April 2011 (UTC)

By the way, the change was initially made by an IP, with no edit comment, and I reverted it as vandalism. If that first edit was actually in good faith (perhaps it was Jc3s5h not logged in) I apologise for the accusation of vandalism. I should have assumed good faith. Mitch Ames (talk) 04:16, 3 April 2011 (UTC)

Dead link

During several automated bot runs the following external link was found to be unavailable. Please check if the link is in fact down and fix or remove it in that case!

• http://www.math.csusb.edu/faculty/susan/number_bracelets/mod_arith.html
  • In 12-hour clock on 2011-05-23 02:24:08, 404 Not Found
  • In 12-hour clock on 2011-06-01 03:24:08, 404 Not Found

--JeffGBot (talk) 03:24, 1 June 2011 (UTC)

Dead link 2

During several automated bot runs the following external link was found to be unavailable. Please check if the link is in fact down and fix or remove it in that case!

• http://physics.nist.gov/GenInt/Time/early.html
  • In History of robots on 2011-03-30 03:41:02, 404 Not Found
  • In History of timekeeping devices on 2011-04-01 02:14:27, 404 Not Found
  • In 12-hour clock on 2011-05-23 02:24:08, 404 Not Found
  • In 12-hour clock on 2011-06-01 03:24:17, 404 Not Found

--JeffGBot (talk) 03:24, 1 June 2011 (UTC)

Table in lead section should be consistent re 12 midnight, noon, am, pm

These changes by Dbfirs removed any reference to m or pm for 12 midday in the table to "avoid controversy". This appears to be a reasonable compromise, but for the sake of consistency we should also change the first and last rows to "12 midnight" (keeping the start/end of day and asterisk). Mitch Ames (talk) 13:52, 16 September 2011 (UTC)

Introduction section

The sentence regarding the am/pm variations is redundant. The Abbreviation section addresses the topic in detail. I'll remove the redundant information. JackOL31 (talk) 18:08, 13 December 2009 (UTC)

There is a sentence which says that the indication of noon and midnight is disputed. I cannot find any verification for this statement. I see where there is confusion, especially where the 24-hr system is predominant, but never any documented dispute. For manufacturers of timepieces with an am/pm indication, I have consistently seen the 12 o'clock hour displayed as shown in the table. Could someone cite references documenting a dispute involving the correct designations for the 12 o'clock hour? JackOL31 (talk) 18:48, 13 December 2009 (UTC)

In the accompanying table you will see (with references) that the U.S. Government Printing Office defines noon as 12 a.m. and NIST as 12 p.m. Those together document the dispute. −Woodstone (talk) 19:19, 13 December 2009 (UTC)

Thanks, I already checked that. That is an old version and the errata has been corrected. The latest version, the 30th Ed, identifies it correctly. The Style Manual is not govt statutes or administrative code. It's just a writing guide. Other documentation would be req'd, especially in light of the revision. JackOL31 (talk) 19:26, 13 December 2009 (UTC)

I just double-checked. I see the 30th Ed (2008) indicates:

b. Clock time (see also Time):

4:30 p.m.; half past 4

10 o’clock or 10 p.m. (not 10 o’clock p.m.; 2 p.m. in the afternoon; 10:00 p.m.)

12 p.m. (12 noon)

12 a.m. (12 midnight)

 JackOL31 (talk) 19:34, 13 December 2009 (UTC)

Hmmm, looks like all of your references to the time at midday and at midnight are out of kilter. I spent 32 years in the military and then another 12 in the aviation regulation business and I can tell you that 12 am is midday andd that 12 pm is midnight. Look at it this way: both noon and midnight last for an infinitesimal amount of time. right up to the instant of 12 am is still a morning time and then it trips over into the afternoon. Towards midnight the time is always pm until that picosecond after 12 pm when it becomes a morning time which is always the am.

To do it the other way is silly as a piece of logic. Twelve, midday, is not the start of the afternoon it is the end of the morning. So 12 am is the last instant of the morning, just as 12 pm is the last instant of the after-noon. To get it straight in your mind just think of what that word afternoon means. If you're finding it hard let me tell you that 12 am is noon and after that you have all of the pm (times) hours.

If you don't like my logic try calling your local weather service or aviation service provider, or even the FAA's FSDO representative anyt any major airport.

I'm seriously shocked that the USGPO now says that it is the wrong way about. My copy of of their Style Manual from 1963 has it the way I explain above for the reason I have said. Maybe the 30th Ed of 2008 was edited by someone who is misconceived too? Lin (talk) 05:19, 22 January 2010 (UTC)

Long discussions (now archived) and references have established that 12:00 a.m. is commonly meant to be midnight, so 12:01 a.m. is one minute later to match. You will see this usage on any computer set to 12-hour display. −Woodstone (talk) 09:47, 22 January 2010 (UTC)

The use of "undefined" is not the most appropriate term for the 12-hour cell since 24:00 does not exist in the 12-hour world. This article is from the 12-hour system perspective (left-handed) and right-handed time notation does not exist. As a general rule of thumb for table entries where a cell exists but no value applies to the situation, an entry of "Not applicable" is made. JackOL31 (talk) 01:43, 15 December 2009 (UTC)

This table does not compare general English words. It compares 1-to-1 clock values. The concept of 24:00 does not exist, not applicable to the 12-hr system. My edit is reasonable and valid. Please discuss if there is disagreement. JackOL31 (talk) 12:11, 15 December 2009 (UTC)

Midnight at the end of a day is certainly an existing time that is expressed in English language. Many opening hours or contract durations involve that time. Therefore "not applicable" is not a correct description. There is just not a simple unified short way of writing it.

The statement of usage of a.m./p.m. at 12 o'clock is only meaningful for digital clocks (not analog ones). Mentioning that specifically is useful information in view of the ambiguity.

−Woodstone (talk) 12:52, 15 December 2009 (UTC)

However, here we are not talking about clocks per se, analog or otherwise. We are showing the 1-to-1 relationship between the two systems. The words are added for clarification, but midnight end of day does not exist in the 12-system. In conversation one can say specifically midnight end of day, but it does not translate into a value in the 12-hour system. Why do you not think people will understand "n/a", it is a common enough concept? (I do appreciate the dialog) JackOL31 (talk) 13:09, 15 December 2009 (UTC)

Just as an FYI, I have a analog mantel clock that stops chiming and striking after 9PM. It picks up again at 6AM. I have also seen analog wall clocks that have external AM/PM complications. One in particular has a circular complication above the 6 with a small hand that moves clockwise, the left side marked AM and the right side marked PM. JackOL31 (talk) 13:21, 15 December 2009 (UTC)

I am referring to the first table here. The second table I am replying to in the above section. JackOL31 (talk) 13:39, 15 December 2009 (UTC)

In my understanding "not applicable" implies that the mentioned time does not exist. In my view its expression is merely "undefined" in the 12-hour system. A subtle, but real difference. On your (or any) analog clock at precisely 12 o'clock you cannot determine if the marker is a.m. or p.m., since the indicator will be just on the boundary between them. You can still determine if it's midnight or noon, because there are two such boundaries. On a device that just flips between them even that is not clear at the very instant. −Woodstone (talk) 14:24, 15 December 2009 (UTC)

Yes, the time 24:00 does not exist in the 12-hour system. This is why you cannot put a value in the entry next to the 24:00 entry. It simply does not exist. It is not applicable to the 12-hour system, whether anyone personally believes in a timeframe of 24:00-ness or not. What is important is that the 12-hour system does not believe in (i.e. incorporate) this concept and offers nothing regarding it. Consider the situation where one is writing an article on the 12-hour clock and one has never heard of the 24-hour clock system. Would that person be putting an entry of 24:00 (or some equivalent) in the table? Would that person even write out that particular row? The challenge is to look at this from a "12-hour system" perspective and not through a "24-hour system" pair of glasses. This means one must avoid taking concepts from one system and projecting them into another. No matter how hard you try, the Roman numeral system will never have a 0!

Regarding your comment on the limitations of physical timepieces, I don't see how that plays a part in our discussion but I will comment. If a analog timepiece changes to 12:00, I know at that very same instant the AM/PM indicator has toggled to the other value. The marker moves clockwise, so if it's at the "12 o'clock position" (or 6 o'clock position) I know the time, even if it is on the border. Yes, there are limitations to analog clocks, negligible as they are. However, many of them have character and beauty, and are works of art. Digital clocks will always be functional, sterile and butt ugly. That's why tower clocks are analog (real towers). JackOL31 (talk) 01:59, 16 December 2009 (UTC)

The Introduction section states that there exists/existed a dispute between the US Govt Printing Office and the generally understood standard regarding how 12 o'clock is displayed with respect to AM/PM for "beginning of day" and "noon". A excerpt is cited from the US Govt Printing Office Style Guide (29th Ed) and compared to everywhere else you can find the 12-hr standard listed, including the US GPO Style Guide 30th Ed. First, the GPO Style Guide does not set policy, it guides one in producing standard looking documents. Secondly, it cannot be shown that it is anything more than an error in printing. Errors in printed content do not imply a larger meaning. There is no evidence that the GPO intended to dispute the generally understood AM/PM settings for the respective times. Also, in light of the revision which reverses the entries and does a 180 on the meaning, I recommend any discussion regarding a dispute or the 29th Ed contradiction (Confusion section) be removed in its entirety. The table entry should be updated to reflect the most recent 30th Ed and the values contained therein or be deleted. JackOL31 (talk) 16:42, 19 December 2009 (UTC)

Unfortunately, I feel I must add the following to my previous comments. When I bring up additions, corrections or deletions to content, I expect to make those contributions. I'm happy to discuss significant changes and hopefully come to an agreement, but I would not expect my recommendations to be acted upon by someone else. I am capable of implementing my own recommendations and I would expect that as common courtesy. JackOL31 (talk) 17:55, 19 December 2009 (UTC)

If this last paragraph was aimed at me, I apologize. After I read your previous comments, and reread the article, I had to agree with you. I must confess I was too lazy to first discuss the changes here and implemented them right in the page. −Woodstone (talk) 18:33, 19 December 2009 (UTC)

Well enough, it's a good reminder that none of this is so urgent that we can't discuss it first. Anyway, apology accepted and we'll move on. Since you have not commented on my post previous to the last, I am assuming you're thinking it over. If you agree with me, we'll let it sit for awhile to see if anyone else has any thoughts they'd like to share. Then, assuming no objections, I'll go ahead and make the necessary changes. If you don't agree, we can discuss it some more. JackOL31 (talk) 21:46, 19 December 2009 (UTC)

As per my entry of 2 weeks ago (see above, "The Introduction section states..."), I have deleted the reference to a dispute which was not shown. A Style Manual does not carry any weight regarding govt regulations or policies. The most obvious assumption is that this was clearly an error and not indicative of a dispute between the GPO (charged with maintaing publications) and NIST or any other time organization. The complete reversal of this entry in the next edition is more than not indicative of a correction rather than a power struggle within the GPO organization with a new victor emerging. If one is to claim that the GPO intentionally decided to interpret AM/PM differently than what is the generally accepted historical understanding, one needs more proof than a contradictory entry in a style guide. If this entry is to be taken as proof, then we must also conclude that it becomes p.m. at 12:15 in the afternoon and it becomes a.m. at 12:25 in the wee hours of the morning - since these are the only entries the GPO Style Guide makes with respect to the relationship in the 12-hour system.

12 a.m. (noon); 12:15 p.m. (15 minutes past noon)

12 p.m. (midnight); 12:25 a.m. (25 minutes past midnight)

Please discuss if you feel otherwise. JackOL31 (talk) 14:21, 1 January 2010 (UTC)

Along the same lines, I have modified the table to reflect the current 30th Ed info from the US GPO Style Guide. To cite an older edition which has been corrected is improper. Once again, one must consider the most reasonable and plausible explanation in these situations. If an entry in a book is contradictory to common knowledge without explanation and then reversed to agree with common knowledge in the next updated edition, I believe one must first conclude a correction rather that a disagreement within the publishing organization. The most egregious claim was "Two separate official style documents of the United States government disagree on the correct usage." To me, it appears to be stated in that manner to avoid stating that it was the same style document, with the latter being the most current revision. JackOL31 (talk) 15:03, 1 January 2010 (UTC)

While trying to verify the statements of Lin above I stumbled on the following document from a very official organisation. It contains:

Career Opportunity, U.S. Department of Transportation, Federal Aviation Administration

Announcement Number: AAC-AMH-08-GAV-006-10911; Opening Date: Oct 16, 2009; Closing Date: Sep 30, 2010

Your application must have a status of "Submitted" before 12:00 AM (midnight) Central Time on the Close Date for it to be accepted.

Logically this can only mean that a submission at any time during Sept 30 will be rejected. A 12 AM midnight on a date is surely not after the noon of that day. However I am fairly sure they mean that any submission on Sept 30 is still valid. Furthermore it contradicts Lin's claim about aviation. −Woodstone (talk) 16:46, 22 January 2010 (UTC)

I grew up in Kenya and remember that on New Years eve we waited until 12 pm for the New Year to roll around. I remember being quite amazed to find that in the United States noon was now 12 pm instead of midnight. Metricmike (talk) 01:07, 6 September 2010 (UTC)

It appears that in the original 12 hour time "system" the anti meridiem and post meridiem refer to hours past the hour of noon (the meridiem), therefore 12 noon was neither am nor pm and midnight was both 12 hours anti meridiem and 12 hours post meridiem. Perhaps this is why there is so much confusion. No amount of official US Government documents will clear this up because other countries and other people have a different concept of am and pm. In Kenya the locals count the hours from sunrise to sunset only, if the sun rises at 06:00 that is zero hour, then noon is 6 o'clock and 4 pm is 10 o'clock. I believe this was the case in all ancient societies until the invention of the (church) clock which could run 24 hours a day. Metricmike (talk) 01:20, 6 September 2010 (UTC)

The table in the introduction section has an inconsistency. The 12-hour entry associated with the 24-hour entry of 24:00 reads - (end of day) '(shown as start of next day)'. This is not correct. The 12-hour system, as far as the nomenclature is concerned, has no equivalent to the 24-hour artificial construct of 24:00. It simply does not exist within the 12-hour system. I believe a more appropriate entry would be 'n/a' or 'not applicable'. When I look up the meaning of 'n/a' in wiki, I see the definition listed, in part, as - for not applicable or ..., used to indicate when information in a certain field on a table is not provided, either because it does not apply to a particular case in question or... . Isn't that the situation we have here? Note: I addressed this issue in more detail in my 16 December 2009 entry. JackOL31 (talk) 20:04, 8 September 2011 (UTC)

It is my intent to change the (shown as start of day) to (not applicable) at some point in time in the future JackOL31 (talk) 21:42, 9 September 2011 (UTC)

It might be better to remove the row completely. Is midnight end of day part of the "12-hour clock"? What is the purpose of the table anyway? See previous related discussions regarding the other table in the article, at #Confusion at noon and midnight - table - midnight, end of day, for clocks and #Confusion at noon and midnight - Table - Digital 24-hour clock displays. Mitch Ames (talk) 06:05, 10 September 2011 (UTC)

Don't you think it's better to leave it open here and discuss the controversy in the later paragraph. I agree that a millisecond after noon is displayed as 12:00 (:00.001) p.m. (indicator) on most clocks showing a 12-hour display. Dbfirs 21:48, 17 March 2012 (UTC)

Americanised article

All times seem to be expressed with a colon, in other places a dot is more common. In the UK, it's not only more common, it's the rule. No mention of this in the article. Also no mention that minutes past the hour below ten can be expressed as a single digit. Five o'clock can be written 5.00 or 5.0 and five past five can be either 5.05 or 5.5 91.85.176.36 (talk) 17:59, 1 June 2011 (UTC)

The colon is not necessarily "American" - it's used in Australia also. Likewise, ISO 8601 uses a colon (albeit with a 24-hour clock). MOS:TIME says "... 12- or 24-hour clock ... in both, colons separate hours, minutes and seconds". I've added a sentence to Typography to mention the variations. Mitch Ames (talk) 11:13, 2 June 2011 (UTC)

I've never understood why the dot is "the rule" in the UK. I've never used it here because it causes confusion with decimal notation. I disagree about 5.5 being a valid time. Dbfirs 16:27, 24 June 2011 (UTC)

I don't know about its use in a 12-hour clock system, but 5.5 is a valid time in ISO 8601. Quoting ISO 8601:2004(E), clause 4.2.2.4 Representations with decimal fraction, with my bold emphasis added:

If necessary for a particular application a decimal fraction of hour, minute or second may be included. If a decimal fraction is included, lower order time elements (if any) shall be omitted and the decimal fraction shall be divided from the integer part by the decimal sign specified in ISO 31-0, i.e. the comma [,] or full stop [.]. Of these, the comma is the preferred sign. ...
... Example: 23,3

Mitch Ames (talk) 06:02, 25 June 2011 (UTC)

Yes, thanks for pointing that out, and I agree that 5.5 would logically mean 5:30, but I was replying to 91.85.176.36 who claimed otherwise (and I'm sure the claim is wrong). Dbfirs 21:37, 8 September 2011 (UTC)

Sorry but 5.5 and it's a valid time - five past five; it's what people use, even if it's not a "decimal notation" or whatever. Considering you claim to be a retired teacher with a BSc and live in England, then you have undoubtedly come across a single digit being used for minutes, it was much more common before digital clocks became influential. So I think you're trying to be a clever dick. 109.176.205.145 (talk) 08:11, 22 April 2012 (UTC)

We don't insult each other here on Wikipedia. I don't know who you are, but please retract the last comment. I have come across single digits being used in pupils' work, and I have advised that this strange usage is ambiguous and open to misunderstanding. Dbfirs 08:33, 22 April 2012 (UTC)

Can't find scans of the tv guide in the Metro or Mail, who use a single digit notation, but here's an old TV Times, couldn't find a more recent scan: [2]. I'm not going to pretend that it's the most common way of displaying time these days, but it WAS the most common form in the UK some years ago, and remains perfectly valid and understandable to everyone but you! 109.176.205.145 (talk) 08:27, 22 April 2012 (UTC)

Thanks for the link. I must admit that I had forgotten the confusing Radio Times usage. Is it still in use anywhere? Dbfirs 08:33, 22 April 2012 (UTC)

Blank line in the table

 Done

There is now a blank line in the "Time as denoted by various devices or styles" table for the entry "Written 12-hour time", with - and ** marks and the ** footnote has been removed. Either the footnote needs to be restored, or the "Written 12-hour time" line needs to be removed.

174.253.236.234 (talk) 14:56, 5 January 2012 (UTC)

The relevant edits that brought about this situation are [3][4][5]. The solution is not clear to me at the moment - I might come back at look at this later. Mitch Ames (talk) 13:21, 6 January 2012 (UTC)

Looks like it's fixed now. Mitch Ames (talk) 03:53, 7 January 2012 (UTC)

All this talk about writing - what about reading?

I came to this article to try to find an answer, when someone writes 12:00 am what do they mean? I have an assignment that must be performed at 12:00 am. Am I to do this job at 12 noon, or 12 midnight? The article is absolutely no help. What I need to know is "What do most people mean when they write 12 am?" Of course, the answer will be imprecise, because some people mean midnight and some mean noon. But what do MOST people mean? Is it safer to assume noon, or midnight? (Obviously, for my assignment, the best approach is to ask for clarification, which I have done. But I haven't received an answer yet, and I need to do the task today if at all possible. The nature of the assignment is such that either answer is entirely possible, no help in deciding which is meant.)

174.253.236.234 (talk) 15:03, 5 January 2012 (UTC)

Most people seem to mean midnight (and I think that was what I was taught many years ago, but I've never used the convention because I considered it to be illogical, having also been taught the meaning of the Latin words). My clocks and watches all read 12 noon a few minutes before the local noon or meridiem. Dbfirs 21:46, 5 January 2012 (UTC)

According to the article, see 12-hour_clock#Confusion_at_noon_and_midnight, if you are in Japan or the U.S. Government Printing Office, the situation might be different. Dbfirs 22:00, 5 January 2012 (UTC)

I have rectified the issue regarding 12:00 a.m. and 12:00 p.m. mentioned earlier. Although we may see recommendations to avoid confusion at midnight (b.o.d.) and noon, the actual nomenclature for those points of time is a.m. and p.m., respectively. Regarding the 1953 Ed. for the GPO, I do not see the point of having it in there. It was simply a style manual with an error. The article misleads readers to think the govt actually used 12am/12pm in that manner. While it is humorous to see the error, I'm confused as to why errata from a 60-year old reference is cited. Errata is not allowed to die, even after it has been corrected (2008 Edition)? JackOL31 (talk) 20:54, 17 March 2012 (UTC)

Apologies for "unrectifying" the issue, but I'm not sure that the convention is universal, even if the 1953 GPO claim is just an error. Dbfirs 23:46, 17 March 2012 (UTC)

Woodstone seems to think that the "rectification" was correct, so I'll accept the viewpoint since I agree that the article ought to show clearly the usual convention, though I still think that it is neither universal nor logical. Dbfirs 20:50, 18 March 2012 (UTC)

As I mentioned in a different talk section, 12:00 a.m. has always equated to 00:00, in 24-hour terms and similarly 12:00 p.m. has always equated to 12:00 in 24-hour terms. You seem to be basing your doubt on a Japanese blog and an error in the 1953 Ed. of the GPO's Style Guide. I don't find someone's blog for learning the Japanese language as credible. Also, given that several Japanese companies manufacture watches sold in the US (e.g. Citizen, of which I own one with an am/pm complication), one would have to believe that those companies make watches which rollover the am/pm designation at 12:00 for the US and other markets, yet for domestic comsumption they rollover at 1:00. That is nonsense. Since I lived through much of the time period since 1953 (way too much of it, sigh), I find it disheartening this article gives the impression that the general public was on one time system (as evidenced by timepieces, TV guides, radio, transportation schedules, etc.) while the US government was on a different 12-hour time system. There is actually nothing in this article to substantiate any claim that the 12-hour time system with an am/pm rollover at 1:00 was ever manufactured in watches or that is was used officially by any organization (setting aside any given individual's misunderstanding). However, I do agree that the inclusion of information from a blog and the citing of errata in a style manual, in the manner of which it is cited, misleads the reader into believing the 12-hour system is/was used by some in that manner. JackOL31 (talk) 18:15, 20 March 2012 (UTC)

The problem of clock display arose only with the advent of digital clocks and watches with 12-hour displays, but I agree that all indicators change from a.m. to p.m. at an instant after noon, and never at 1 p.m. I'll accept your claim that the 1953 GPO guide was just a mistake, and obviously a blog is not a reliable source, so we disagree only on the universality of the printed use of 12 p.m. to mean 12 noon and the confusion that this causes. Dbfirs 09:02, 21 March 2012 (UTC)

I don't buy/use digital watches. My Citizen watch is analog. My current watch is an analog, radio-controlled watch. Sadly, this watch has the seconds, A/P indicator, and date in a little LCD display where the VI should be and it's toggled by buttons. Older watches (60's) had tiny windows where am or pm could be seen. Although not common on wall clocks, I've seen an analog wall clock with a dial at the bottom which rotates pointing to the left side (am) and the right side (pm).

I agree that 12:00 am/pm causes confusion, but education could fix that. However, it's not something most people care passionately about unless you're a wiki editor. Obviously, the 24-hour system is better suited for most tasks, such as timestamping transactions (sortability) and nonambiguous situations (military, etc). I just don't care for it much in casual use. JackOL31 (talk) 13:26, 21 March 2012 (UTC)

The whole problem arises because we have tried to adapt a logical Roman usage to our modified numbering system with 12 meaning noon. Originally, the Romans had it correct with 0:00 (a.m. or p.m.) meaning noon, and 1 a.m. meaning our 11 a.m. and 2 a.m. our 10 a.m. etc. The problem with trying to use education to fix the confusion is that the system is illogical, so I'd prefer to fix the system, but Wikipedia reflects usage, not determines it, so this is the wrong place for my campaign! I'll shut up now! Dbfirs 20:43, 21 March 2012 (UTC)

I don't believe Lin is a reliable source. I myself spent 5 years in the military, and from basic training on we used only 24-hour time, where noon is 1200 hours. We never used am/pm except when dealing with civilians, and even then we understood exactly what they meant.

• Civilian 11:59 a.m. is one minute before noon - 1159 hours military
• Civilian 12:00 p.m. is noon - 1200 hours military
• Civilian 12:01 p.m. is one minute after noon - 1201 hours military

For artillery barrages and airplane flights, the distinction between 12 o'clock in the daytime and 12 o'clock at night is crucial - literally a matter of life and death. So we avoided all ambiguity with 24-hour time. Noon was never a problem, because it was simply 1200 hours (but a wise sergeant might emphasize that this was "around lunch time" or "at noon" just to be sure he was understood). --Uncle Ed (talk) 16:22, 1 May 2012 (UTC)

Confusion just after noon or midnight

The acronym "pm" means literally "after noon", but nowadays it is interpreted as "in the afternoon". So 30 minutes past noon -- that would be denoted literally as 0:30 pm -- is to be denoted instead as 12:30 pm (not to be interpreted literally as 12 hours and 30 minutes past noon, which is actually just 30 minutes past midnight). Have you seen any references for that? Fgnievinski (talk) 01:05, 4 April 2012 (UTC)

You seem to be trying to force your purists notions onto establish usage. The term ante meridian (a.m.) refers to the 12 hour period before the meridian. This is all the time from midnight, through sunrise, until noon. The other term post meridian (p.m.) refers to the 12 hour period coming after the meridian, from noon through sunset to midnight.

The problem lies with the precise, to-the-minute denotation of noon and midnight. As a computer scientist, I can tell you gladly that this problem has already been solved! When we say BETWEEN we use the term inclusively. All children between the ages of 6 and 12 includes six-year-olds and twelve-year-olds. Otherwise, we indicate exclusive denotation by using worlds like greater-than or less-than. "Children less than 16 years old are not allowed to have a driver's license."

So we use a.m. for everything beginning at midnight (before sunrise) and continuing up to (but not including noon).

• 12:00:00 a.m. is midnight
• 12:00:01 a.m. is one second after midnight (only of interest to bankers or database professionals)
• 12:01 a.m. is one minute after midnight (used by airlines, trains, and buses).
• 11:59 a.m. is one minute before noon
• 12:00 p.m. is noon

Now you might wonder how 12:00 P.M. can be "12 hours past the meridian", but that is not what it means. All times referring to the period which begins at noon and continues until a moment before midnight are considered to be "post meridian". This is established usage, whether it seems sensible to you or not. And our article must describe actual usage, not the reformist ideas of contributors such as you or me. --Uncle Ed (talk) 16:36, 1 May 2012 (UTC)

This edit only adds to the confusion. In particular:

• "12:xx" (assuming "xx" is a number) is never going to refer to "the 60 minutes" - it's going to refer to one minute. Should this says "60 seconds"?
• Is there really any citable scenario where "12:30 am" means 30 minutes after noon or "12:30 pm" means 30 minutes after midnight?
• The reference to "12:xx" is not consistent with "some style guides [replace '12:00 pm' by 'noon' ...]. It's probably not appropriate to replace "12:30" with "12:30 noon" or "12:30 ...midnight". The reference to the style guide is probably only meaningful for 12:00, not 12:xx.
• "... recommending replacing '12:00 p.m.' by '12:00 noon' ... " should probably be "... replacing ... with ...".

Mitch Ames (talk) 00:35, 3 May 2012 (UTC)

Yes, I agree on all points. The strange claim has now been edited out by Woodstone. Dbfirs 11:53, 3 May 2012 (UTC)

Listing every hour in the Clock System table

24.88.105.16 has repeatedly [6][7][8] tried to add every hour to the Clock System table in the lead section, and it keeps getting reverted [9][10][11] as unnecessary. (To be fair, I think the last couple of additions/reversions should be treated as one. It appears that our edits overlapped.) I think that listing every hour is unnecessary and simply clutters up the page. The patter is obvious with only the hours either side of midnight and noon listed explicitly. Do other editors have an opinion on this? Mitch Ames (talk) 03:10, 9 April 2012 (UTC)

Note that my last edit was not a reversion of the IP's edits. The extra hours were not added by the IP in this recent edit-war, but I think they're unnecessary so I've removed them. Mitch Ames (talk) 03:14, 9 April 2012 (UTC)

I've just reverted again the addition of intermediate hours from the table. This addition was by a different but similar IP - so probably but definitely the same editor? Would the IP(s) please discuss the matter here. Do other editors have an opinion on the matter? Mitch Ames (talk) 11:42, 14 April 2012 (UTC)

For myself, I think it looks better to have the complete table. Seeing only 12s, 11s, and 1s looks silly to me. However, I don't feel that strongly about it that I would put a lot of effort into the matter. Whatever others decide is okay. JackOL31 (talk) 05:24, 16 April 2012 (UTC)

Confusion at noon and midnight - text

[Since the Latin word meridies means noon or midday, it is illogical to refer to noon as either "12 a.m." ("12 ante meridiem", or "12 o'clock before noon") or as "12 p.m." ("12 post meridiem", or "12 o'clock after noon"). On the other hand, midnight could logically be called either "12 p.m." (12 post meridiem, 12 hours after the previous noon) or "12 a.m." (12 ante meridiem, 12 hours before the following noon); "x a.m." no longer means "x hours before noon", but "x hours into the day but before noon" or "x th hour before noon".]

really this whole beginning is nonsensical and without any citation -- it appears to be an invention from someone who looked up the latin terms for AM & PM and then used some sort of convoluted "logic" to create an issue. Yes, there is confusion and there are people who do not know whether 12 pm refers to noon or midnight -- but that's only because they don't know which designation means noon & which one means midnight, they aren't confused by the latin.

In common parlance in the USA, which predominantly uses a 24 hour clock, the answer is far simpler than this invented, uncited rationale: 12 pm has always meant noon. Period. End of story.

& that's the main thing people want to know who are confused about whether 12 pm means noon or midnight, not the invented rationales for why there's no answer, when there is a correct answer.

If another culture or nation that uses a 24 hour clock uses 12 am to mean noon & the reverse, please go ahead and cite a legitimate source.

This passage: [The American Heritage Dictionary of the English Language (Fourth Edition, 2000) has a similar usage note on this topic: "Strictly speaking, 12 a.m. denotes midnight, and 12 p.m. denotes noon, but there is sufficient confusion over these uses to make it advisable to use 12 noon and 12 midnight where clarity is required."]

& the subsequent attempts to support the invented rationale of the opening paragraph of this section do NOT speak or give support to the above invented issue -- it simply notes that there's "confusion" over which denotes which, but not because of any reference to the latin terms or when the sun is straight overhead. People just don't know because they usually use "noon" or "midnight" whenever there's any chance of confusion. & each subsequent citation example that speaks to this issue simply ends w/ the same -- 12 pm means noon, 12 am means midnight, & they acknowledge there are people who don't know this.

IMHO, invented controversies in passages such as the above hold wikipedia up to the ridicule & disdain it sometimes rightly deserves. Might as well give some space to the flat earthers on the "Earth" entry.

Mover2100 (talk) 16:49, 14 June 2011 (UTC)

I'd like to say I completely agree with Mover2100, though I'd like to add just a few points.

First, to reiterate and paraphrase the most important point given by Mover2100: People coming here typically want to know what 12 am and 12 pm are defined to be, not the ambiguity argument. Period.

In Meridian (astronomy) it says, 'The term "meridian" comes from the Latin meridies, which means both "midday" and "south".' So if you define midday -- or even noon, for that matter -- as when the sun crosses the meridian, then you need to know that this pretty much never happens at 12:00 civil time (see Equation of Time), hence invalidating the reasoning of the argument that 12 am and 12 pm are ambiguous.

And not only is 12 am defined to be midnight and 12 pm defined to be noon; it's the only sensible way for them to be defined. This way, am/pm simply becomes another column in the time that rolls over the same way the other columns do. As an example, the following sequence is in chronological order:

10:58:59 am

10:59:00 am

11:00:00 am

12:00:00 pm

To be explicit, the value in any given column is incremented whenever the column of the next smaller unit rolls over. (Well, it is a little odd to have the 12-hour unit follow the seconds column, but my reasoning stands. It's like month/day/year being out of order, with the rollover function still being in effect.) As a further example I once had an am/pm digital clock with mechanical flaps. The flaps in the hours column had values of 12 am, 1 am, . . ., 11 am, 12 pm, . . . -- you get the picture. It would take a lot of work to get the words "noon" and "midnight" in there!

Re "confusion": There is confusion over a lot of things, like spelling. That doesn't mean we can't establish or define "correct" spellings.

As far as the Latin definitions go, this is English in modern times. Words don't always mean what their etymological origins are. Check out the verb "boot" (as in booting your computer), for example.

OK, I better stop now or I'll exceed "a few"! --Betaneptune (talk) 13:30, 2 September 2012 (UTC)

This statement appears incorrect to me - On the other hand, midnight could logically be called either "12 p.m." (12 post meridiem, 12 hours after the previous noon) or "12 a.m." (12 ante meridiem, 12 hours before the following noon);. I see no indication in this article nor anywhere else that the designations of am/pm refer to anything other than that specific day, i.e. they are relative terms - relative to the day in which the specified noon occurs. However, 12 hours after the previous noon is 12:00 a.m. the next day. Once again I believe we are falling in the trap of describing the 12-hour clock within the context of the 24-hour clock instead of the other way around. It do not see how it can be logically called 12:00 p.m. of the same day. I would say this entry needs to be removed or reworded. JackOL31 (talk) 20:21, 8 September 2011 (UTC)

I think the sentence is just pointing out the logic of "12 hours after noon gives midnight" (not necessarily the next day). I agree that the article would benefit from a re-write in a more factual and less opinionated style. Dbfirs 21:48, 8 September 2011 (UTC)

If we're going to re-write the article (and possible even if not), I suggest we should consider renaming it, eg to "12-hour clock system" or similar, because it's about the "time conversion convention", ie how we denote time - not just about physical clocks. (Many 12 hour clocks do not include an am/pm indicator at all.) Actually, there is quite a bit that's common between this and the 24-hour clock article, and it is almost impossible to talk about the 12-hour system without defining it by reference to the 24-hour system. Perhaps we should seriously consider merging the two articles. Mitch Ames (talk) 12:06, 9 September 2011 (UTC)

This article is about "the" 12-hour clock, not about "a" 12-hour clock. Adding "system" is wholly unnecessary and would be a change to a less common name. I agree about the relative nature of the clock times. There is no logic in using 12:00 p.m. for midnight at the beginning of the day. −Woodstone (talk) 15:49, 9 September 2011 (UTC)

I would like to see the entire first paragraph under Confusion at noon and midnight replaced. I suggest something along the lines of: Although the Latin word meridies means noon or midday, the de facto convention is to use the designation of post meridiem for 12 o'clock noon.

The x a.m. information is repetitive (See History and use) and should be deleted. JackOL31 (talk) 21:35, 9 September 2011 (UTC)

Woodstone, I disagree that "This article is about 'the' 12-hour clock ... adding 'system' is unnecessary". Using a definite article instead of an indefinite article doesn't change the meaning of the noun-phrase "12-hour clock". If it does make a significant difference, should the article be renamed to "The 12-hour clock"? I don't think so - and WP:DEFINITE also says we should not. But if "the 12-hour clock" is so different to "a 12-hour clock", we have a problem, because we need an unambiguous title. As the first sentence says, this article is about "a time conversion convention", not "an instrument used to indicate, keep, and co-ordinate time". I think that the article title should clearly reflect the contents, which are not limited to the physical clock. Mitch Ames (talk) 06:25, 10 September 2011 (UTC)

In On the Town (Gene Kelly, MGM, 1949), the sailors are on shore leave for 24 hours, and the time is shown occasionally at the bottom of the screen. Noon is shown as "12:00 M" (= meridies). (Midnight is not shown.) Was this perhaps an earlier convention that has fallen into disuse? But maybe we should not even bring this up.... Grommel (talk) 01:59, 10 July 2012 (UTC)

I added a section to state how in some signs for commercial establishments in Japan, they state closing time of greater than 24, such as "Open from 11:00 to 28:00" to indicate 11:00 to 04:00 (next day) which reduces the potential for confusion with operating from 11:00 to 16:00. I can't find a specific document stating this standard but referenced one English web page that states this for a mall. A search for "open until 28:00" shows many results, mostly from Japan including photos of signs as well as web pages Hv8EEHpq (talk) 23:48, 23 November 2012 (UTC)

"clock system" table - midnight and noon

I've changed the "clock system" table again, to show the numeric time first, then midnight/noon in brackets. The number is first because that's what the clock actually shows. Midnight/noon is a clarification for the reader so in brackets. I've removed "start/end of day" because it's self-evident, and covered by 12-hour_clock#Confusion at noon and midnight. Mitch Ames (talk) 02:16, 4 February 2011 (UTC)

The article is about the system of the 12-hour clock, as header of the table indicates. That is not just what a (digital) clock shows, but the full denotation of time. The last row is about midnight at the end of the day. At midnight the date changes. Which date prevails is an issue. In the 24-hour clock midnight at the end of 31 Januari can denoted as 24:00 (this is not uncommon in contracts). In the 12-hour clock you would never denote the same instant of time as 0:00 a.m. on 31 Januari. Therefore it does not make sense to put 0:00 in the last row. −Woodstone (talk) 04:47, 4 February 2011 (UTC)

I concede your point about the system being more than just the display in a clock, and I'm not going to quibble over the order of (for example) 12:00pm vs noon. However I still think that the table needs changing, because:

• The 12-hour clock system must surely include actual physical clocks, both digital and analogue - it's a clock system, not a time system - so we should include in the table the time as shown on most clocks at midnight. I've yet to find one that actually says "midnight" on the analogue face or digital display. Note also that the article's lead paragraph says "Each period consists of 12 hours numbered: 12 (acting as zero) ..." No mention there of midnight.
• Similarly the 24-hour clock system must surely include physical 24-hour clocks - a good many of which display 00:00, not 24:00.

Thus I suggest that the "midnight" row should show "midnight (end of day) 12:00 am *" and "24:00 (end of day) 00:00 (start of next day). Mitch Ames (talk) 08:58, 4 February 2011 (UTC)

In the 12-hour clock the time midnight at end of day cannot be denoted meaningfully by 12:00 a.m. That notation is only meaningful for begin of day (although not totally unambiguous, since it sometimes might mean noon as well). :Since midnight at end of day is the same instant as midnight at begin of the next day, a physical digital clock cannot display both. It has to make a choice. In the 12-hour clock the only available choice is never to display end of day, but skip right to 0:00 a.m. the next day. So the last line should be blank. In practice almost all digital physical 24-hour clocks do the same, going right to 00:00. This is especially clear on clocks that have a date display as well. There are some very exceptional cases of a clock (without date) actually showing the end of day as 24:00 for a full minute. IMHO not worth summarising in the table.

In written notation, the 12-hr clock still has no notation for end of day. So work-arounds like 11:59 p.m. are used. In the 24-hour clock the notation 24:00 is clearly at the end of the implied or written date, and is regularly used in time schedules and especially in contracts (validity form begin of first day till end of last day).

−Woodstone (talk) 13:47, 4 February 2011 (UTC)

I understand and agree with most of what you're saying - but I still think the table needs entries in those cells. Our disagreement appears to be about the purpose of the table, rather than how a particular time should be denoted. The purpose of the table is not stated in the article, but perhaps it should be. It might help if you answer these questions:

1. What is the purpose of the table? Ie what exactly is it intended to show?
2. Does a "clock system" include actual physical clocks? (If not, perhaps the table and the article need renaming.)
3. As a reader of the article, I assume that the table shows me what a digital clock would show at a given time. Is this assumption correct and/or reasonable? (If not, the article needs to address Q1 above.)
4. Is "midnight end of day" a meaningful time? (eg I went out at 7pm on Saturday for dinner and a movie, and returned home at midnight the same day.)
5. If yes, what would I see on my digital clock at that time?
6. Why isn't the answer to Q5 in the table? (See Q1, Q2, Q3.)

Perhaps (depending on the answers to Q1, Q2, Q3) the table should be expanded to have three columns: Notation when writing the 12-hour time (existing "12-hour" column), Time displayed on 12-hour digital clock, 24-hour notation. For 24:00 in the "12-hour digital clock" column we would put "12:00a (of the next day)". Mitch Ames (talk) 03:09, 5 February 2011 (UTC)

I'm assuming for now that the results of this discussion will be similar to that of #Confusion at noon and midnight - Table - Digital 24-hour clock displays below, so there's probably not much point in trying to have both discussions at once. Once the matter below is resolved, the answer here should become more clear. Woodstone, can I suggest that you add the asterisk back to the "midnight (end of day)" row of the table. Regardless of our differing opinions as to the 1st column should show a number, presumably the asterisk still belongs. Mitch Ames (talk) 12:55, 11 February 2011 (UTC)

(moved from below and edited to fit) I have put (shown as start of next day) in the table. That recognises the validity of the demarcation, without suggesting that there might be 3 different times 12:00 in the 12-hour clock. For me it's a good compromise. −Woodstone (talk) 12:16, 12 February 2011 (UTC)

:Are you referring to the table in the lead section or the table in the "Confusion at noon and midnight" section. If the former, could you please move (or copy and strikethrough here) your comment up to #"clock_system" table - midnight and noon. There are two tables in the article, with different formats and potentially different requirements (although the discussions are clearly related), and it might be easier if we keep the discussions separate. Mitch Ames (talk) 12:50, 12 February 2011 (UTC)

Looking at the Clock Systems table, I do not understand the issue with 12-hour notation entry for start of day listed as 12:00 a.m. and the entry for noon listed as 12:00 p.m.. That is what it is actually denoted by on 12-hour timepieces which carry an am/pm indicator. Regardless of whether we consider timepieces or not, that is the 'de facto' notation for those points in time in the 12-hour system. To simply put an 'asterisk' or the term 'noon' does not reflect the 12-hour time system as it is used. The point regarding possible confusion is still made numerous times elsewhere in the article and we don't have to overdo it in this table. The value of 12 a.m. for beginning of day, despite the claim in the article, is a consistent notation since am/pm is relative to noon for that day and the notation does not span days. Therefore, 12:00 a.m. (beginning of day) is most certainly in the same day and is most definitely ante meridiem. Now 12:00 p.m. is a misnomer since noon is not post meridiem, however it IS the de facto usage for that time occurrence. I believe we are over thinking this. Lastly, midnight end of day does not exist (i.e. not accommodated) in the 12-hour system but I can go along with the entry used. JackOL31 (talk) 21:55, 23 January 2012 (UTC)

I have made the change I described at the beginning of the previous comment. Clocks with an am/pm complication actually indicate a.m. at beginning of day and p.m. at noon, so the table should reflect that. Regardless of new recommended usage suggestions, the a.m./p.m. system still operates in that manner. The footnote asterisk was retained to directs the reader for more detail. JackOL31 (talk) 20:34, 17 March 2012 (UTC)

... but are we not discussing the 12-hour clock system, not specific clocks? Dbfirs 21:52, 17 March 2012 (UTC)

.Exactly! Specifically in the am/pm system, the time is 12:00 a.m. when it is 00:00 in the 24-hour system and similarly it is 12:00 p.m. when it is 12:00 in the 24-hour system, regardless of whether a physical clock displays the the complication or not. That is how it is denoted in the am/pm system and the table should reflect that information. A recommendation regarding how one should avoid confusion does not change that fact nor did the edit I made change the reference to the addl informational section. BTW - I offered that change 2 months ago without objection. JackOL31 (talk) 23:14, 17 March 2012 (UTC)

But the article is about the 12-hour clock system, not the majority convention on use of a.m. and p.m. I've no doubt that we can find many sources to support your claim that the time is 12:00 p.m. at noon, but also many other sources that advise against using this convention. Dbfirs 23:56, 17 March 2012 (UTC)

Do you have any evidence that the de facto notation for the 12-hour system was somehow changed to eliminate the am or pm designator for the 12:00s? Is the recommendation regarding how to avoid confusion in common usage evidence that it has been removed from the 12-hour system? Are you suggesting clocks with the am/pm designator are not implementing the 12-hour system, i.e. they are implementing some other time system notation? If so, where is the wiki for that time system? Why wouldn't the actual implementation of the 12-hour system on timepieces be evidence that beginning of day is represented by 12:00am and noon is represented by 12pm in the 12-hour system?

If any one of the millions of people worldwide looks down at their 12-hr clock on a MS Windows PC and sees the value '12:00 AM' or '12:00 PM' displayed, why can't they go to the wiki on the 12-hour system and find that entry in the 12-hour table? JackOL31 (talk) 14:42, 18 March 2012 (UTC)

Well I agree that the article should show the common convention, but I'm not convinced that it is an essential part of the 12-hour clock system, nor that it is logical. I'll accept your addition for the sake of helping people who want to know what 12 a.m. usually means. Dbfirs 20:56, 18 March 2012 (UTC)

Respectfully, I beg to differ. It is not just a common convention, it is the actual de facto standard and the actual implementation of the 12-hour system for timepieces. It is an integral part of the 12-hour system to have a continuum of time values each having the necessary am/pm designation. Without that designation at each point, the system no longer has a consistent structure. For what it is worth, the 12-hour system does not accommodate dual naming conventions for a single point in time and the naming is relative to the current day. Therefore, 12am is most decidedly ante meridiem and a logical and consistent name for that point in time. On the other hand, 12pm is most decidedly a misnomer for that point in time. However, for good or for bad, the common person does not pay attention to the Latin meanings or the scientific implications of the designations. The designation a.m. simply indicates the first half of the day while the p.m. designation simply indicates the second half of the day (the repeat of the numerical times). In that respect, it is logical and consistent.

I would also add that 12:00 am (SOD) & 12:00 pm (noon) designations are not what they usually mean, but what they do mean. I'll address that in a different talk section. JackOL31 (talk) 18:06, 20 March 2012 (UTC)

We'll have to differ on this, because I believe that using "12 p.m." for "12 noon" is just a common (and confusing) convention, and we have several references in the article for organisations and publications that use 12 noon. The fact that clocks (including Microsoft's display) show a "p.m." indicator for any time after the instant of 12 noon doesn't make the usage of "p.m." for noon a world-wide standard, just a convenience for simplified clock displays. Dbfirs 08:32, 21 March 2012 (UTC)

Anyone want to make a similar change to the table in the 24-hour article? I know if I do it will just be reverted out. JackOL31 (talk) 19:23, 20 March 2012 (UTC)

I think I'll keep out of the argument, too, and let other people decide. I apologise for a hasty reversion of your last edit -- I should have read the whole talk page first. Dbfirs 08:36, 21 March 2012 (UTC)

I can live with differing. However, your belief that the use of am/pm for 12:00 doesn't change the fact that it has always been that way when implemented in timepieces. There is no evidence it has been implemented in any way other than what the table indicates. Indeed, if you look at the hierarchy of how time increments, it makes no sense for it to operate in any other manner (re: The fact that clocks...). To wit, seconds rollover => minutes rollover => hours rollover => am/pm indicators rollover => dates (day) rollover => months rollover => year increments. This is the same manner in which the 24-hour clock system operates sans the am/pm indicator table and the hour table swapped from {12, 1, 2, ... 9, 10, 11} to {00, 01, 02, ... 21, 22, 23}. The system is based on table rollovers with the exception at the top - years. As it appears today, 12:00 a.m. (midnight-sod) and 12:00 p.m. (noon) will always be used on watches/clocks using the am/pm complication, regardless of recommendations how to avoid confusion in communications. One has nothing to do with the other. I'll stop now, the horse is looking over-tenderized.

I thought it was a bit hasty since it wasn't flagrantly wrong and no talk had taken place, but no harm done. JackOL31 (talk) 12:50, 21 March 2012 (UTC)

Yes, I was tired and had mis-remembered the earlier contents of the talk page. Thanks for not taking offence (offense). Dbfirs 20:57, 21 March 2012 (UTC)

First, 12:00 am is midnight at the beginning of the day and 12:00 pm is 12 hours later. As I said in the previous section, this is the only sensible way to define these terms. It is what all am/pm digital clocks show. In fact, it is not even practical to make a digital clock any other way. Would those who oppose the sensible and de facto definitions have the clock show the word "noon" for what is, even according to them, an unobservable instant? The time shown by digital clocks is rounded off through truncation. One result is that an am/pm digital clock shows 12:00 am for the first 60 seconds of the day. So why have the first instant of this 60-second period be treated differently? Why define am/pm time to be different than what virtually, if not every am/pm digital clock on the planet shows?

Now, the table should be adjusted as follows:

• First row: 12:00 a.m. | 00:00
• Noon row: 12:00 p.m. | 12:00
• Last row: 12:00 a.m. the next day | 24:00 (same as 0:00 the next day)

The terms "noon" and "midnight" are independent of the clock systems and should either be removed outright; entered in parentheses in the first, noon, and last rows of both columns, respectively; or given their own column. --Betaneptune (talk) 02:50, 3 September 2012 (UTC)

Sorry, I changed my mind about the last row. I have since realized that the last row should probably be omitted. It is not a part of the "clock system" (which is the heading of the table), as no clock (with the exception of a bizarre kitchen appliance clock whose picture once appeared in this article) displays 24:00, nor should it. It would mean that 24:00 would be displayed for 60 seconds and would represent the first 60 seconds of the day, which is ridiculous. The term "24:00" is merely a notational convenience for specifying end of day -- an instant, not a 60-second period, which is what times on clocks do. For example, if you wish to express the period of noon Friday to the end of Saturday [Friday 12:00 thru Sunday 00:00], it's easier to visualize it with the end point being called "Saturday 24:00". If it is to remain in the table then this point should be added. The 12h equivalent should then simply be what I entered above, or possibly

• Last row: 12:00 a.m. the next day or midnight end of day | 24:00 (same as 0:00 the next day)

There is a difference between what a written time specifies and what a time displayed on a clock means. The former is an instant, while the latter is a 60-second period. Betaneptune (talk) 18:13, 8 September 2012 (UTC)

TL;DR

...the above mass debate. But this article might as well have a flag at the top of the page denoting an "American view" which needs to be fixed. This is English language Wikipedia. In the UK, most people use a dot to separate hours and minutes, not a colon. Also if there are fewer than 10 minutes past an hour, it may be denoted as a single figure, i.e. 9.0pm is nine o'clock in the evening, 9.5pm is five past, etc. 109.176.205.145 (talk) 08:03, 22 April 2012 (UTC)

Well I'm English, and I prefer the colon, but I agree that the full stop is common in Britain. I've always considered this bad practice because it can be confused with a decimal point, but this is only my opinion. The single figure minutes of the old Radio Times seems to have died out. Are there any publications that still use it? I've added a mention of this notation to the article, and Mitch Ames has also added it with your reference. Dbfirs 08:37, 22 April 2012 (UTC)

109.176.205.145, remember that is the "English language" Wikipedia, not the UK Wikipedia. As it says in12-hour_clock#Typography

The hour/minute separator varies between countries: some use a colon, others use a period (full stop).

Specific current references describing specific current usages would be helpful if you want to change the current wording. Mitch Ames (talk) 12:45, 22 April 2012 (UTC)

Wording - midnight start of day

Kellyanns made this change

... "midnight" is replaced with "11:59 p.m." for the end of a day or "12:01 a.m." for the start of the next a day.

and Dbfirs reverted it, say that it was "clearer as it was".

However, I'm included to think that Kellyanns' version was more accurate. The context does not limit usage to midnight end of day, so while "midnight" might be ambiguous, its use as beginning of day does not need to be beginning of the next day. Eg a contract for insurance for some future period might start at "midnight, 1 December". This could mean midnight at start of 1 December or midnight at end of 1 December, so to remove the ambiguity we change it to 12:01am 1 December. This is not "the start of the next day" (2 December). In this context Kellyanns's "start of a day" makes more sense than "start of the next day".

Does anybody else care to comment? Mitch Ames (talk) 11:30, 21 October 2012 (UTC)

I concur that the version with "start of a day" is more accurate and not less clear. −Woodstone (talk) 16:14, 21 October 2012 (UTC)

The context is important. The full paragraph was:

The use of "12:00 midnight" or "midnight" is still problematic because it does not distinguish between the midnight at the start of a particular day and the midnight at its end. To avoid confusion and error, some U.S. style guides recommend either clarifying "midnight" with other context clues, or not referring to midnight at all. For an example of the latter method, "midnight" is replaced with "11:59 p.m." for the end of a day or "12:01 a.m." for the start of the next day.

In general, I agree that 12:01 a.m. is "the start of a day", but in this context (substitute for midnight), I still think that "for the start of the next day" makes the paragraph clearer in that the times are two minutes apart with a change of date, rather than 23 hours and 58 minutes apart. Dbfirs 07:15, 22 October 2012 (UTC)

If you want to keep "the start of the next day", the example needs to be expanded to include an actual date and the precise interpretation. If my contract says that my insurance expires at December 25, 2012, 12:01am, does that mean 2012-12-25T00:01 (ISO 8601), or does it mean 2012-12-26T00:01 ("the start of the next day")? Unless there's some specific law that says "When written with a date, 12:01am means midnight at the end of that date" (in which case how do you express 2012-12-25T00:01 in such a contract?), I would interpret December 25, 2012, 12:01am as beginning of Christmas Day (2012-12-25T00:01). However, your preferred wording implies that it means end of Christmas Day ("start of next day"). Possibly what you mean is "midnight December 25 is replaced by "12:01am December 26 - but if that's the case you need to say so explicitly, in particular that the date is replaced (25 -> 26) not just the time (midnight -> 12:01am).Mitch Ames (talk) 14:10, 22 October 2012 (UTC)

Agreed. It all depends on context. This is why insurance contracts don't use midnight. I'd be happy to expand with an example to include dates. Dbfirs 08:50, 24 November 2012 (UTC)

Rounded time and am/pm

The section "Informal speech and rounding off" does not mention examples around noon or midnight. How would you say 11:55 a.m. when rounding off? "5 minutes to 12 a.m." because the present time is still before noon (i.e. "[5 minutes to 12] a.m."), or "5 minutes to 12 p.m." because in 5 minutes it will be 12 p.m. (i.e. "5 minutes to [12 p.m.]")? --81.10.180.26 (talk) 13:22, 15 April 2013 (UTC)

Most likely the am/pm is omitted, and deduced from the context (as noon or midnight), as appears to be the case for the other hours mentioned in that section. But I have no ref ... Mitch Ames (talk) 13:49, 15 April 2013 (UTC)

How can you say time is 12:01 in a 12 hour's system? One minute after 12:00 it must be 0:01. — Preceding unsigned comment added by 193.169.154.69 (talk) 08:34, 12 September 2013 (UTC)

No, it's the 24-hour clock system that uses zero (00:00 hours and 00:01). The 12-hour clock uses the digits 1 to 12 for the hours, changing to 1 p.m. just one minute after 12:59 p.m. Dbfirs 10:32, 12 September 2013 (UTC)

Multiple errors by Woodstone

This edit by User:Woodstone contains two errors. First, the letters "Mi" are inserted at the very beginning of the article. Second the article is altered to say "and p.m. begins just after 12:00 and ends just before 24:00." But in fact, midnight can be regarded as either before noon, or after noon, and to say that midnight belongs exclusively to the day that is beginning, rather than the day that is ending, is wrong. Jc3s5h (talk) 13:09, 24 June 2011 (UTC)

Sorry for accidentally adding two random letters. I was editing on a phone and overlooked it in preview. The question is not if midnight belongs to a certain day, but if 12:00 a.m. does. Clearly, as it is "before noon" of a certain day, it cannot be at the end of that day. If 12:00 is supposed to be midnight, then 12:00 p.m. must logically be (and practically is) noon. In the 12-hour clock using a.m. and p.m., there is no way of expressing the end of a day. This is consistent in the various discussions of the confusion around 12:00 am/pm in the article. −Woodstone (talk) 15:58, 24 June 2011 (UTC)

The United States is a major English-speaking country, so while the published position of the United States government is not the final word on English usage, it can't be ignored either. NIST states "Are noon and midnight 12 a.m. or 12 p.m.? This is perhaps the trickiest time question of them all. The best answer is that the terms 12 a.m. and 12 p.m. cause confusion and should not be used." Woodstone's unsupported statements, on the other hand, can be ignored.

Also read the "Confusion at noon and midnight" section which mentions several reliable sources which either agree with NIST about the ambiguity of am and pm, or express contradictory claims. Jc3s5h (talk) 16:16, 24 June 2011 (UTC)

Funny how the new 12-hour option on NIST's time.gov renders midnight as 12:00 a.m. and noon as 12:00 p.m. Betaneptune (talk) 00:18, 4 April 2014 (UTC)

Context is critical

In interpreting the meaning of "12:00 AM" or "12:00 PM" it is critical to know whether it is displayed by a digital clock, written in a statement that is not part of a clock, or displayed by an analog clock.

In a written statement, one must search for contextual clues to figure out which of 3 times is intended (either of 2 midnights, or (erroneously) the midnight noon between them.

In the case of an analog clock, the same ambiguity is present, because the analog clock can display an instant of time.

In the case of a digital clock that displays the nearest minute, 12:00 AM means the minute following midnight, because except for the first instant of that minute, it is less than 12 hours before the next midnight noon and more than 12 hours after the preceding midnight noon. Similarly, on the digital clock 12:00 PM is the first minute of the afternoon. Jc3s5h (talk) 21:29, 26 June 2011 (UTC)

The above is rather confusing. Did you mean the marked version? −Woodstone (talk) 04:56, 27 June 2011 (UTC)

Sorry, Woodstone's correction is what I meant. Jc3s5h (talk) 08:12, 27 June 2011 (UTC)

Everyone knows that 12:XX AM is morning and 12:XX PM is after noon. This article should address why people mentally for some reason can't fathom what to do when XX is zero, even though its exactly the same as when it isn't zero. If 12:00 AM was noon that would mean the AM to PM change over occurred at an infintesmily small moment *after* noon. So on no clock, digital or otherwise, would you even see 12:00 AM as 1 nano-second later it would be technically be 12:00 PM. People just over think the matter and trick themselves. For example you said some people think there could be 2 midnights given a date. Thats ridiculous. A day starts as 12:00AM. There can be no confusion over any time given for any date. Your example of the digital clock approximating the minute is true of *any* clock. All clocks approximate time down to quanta of a photon. This is why 12:00PM is noon, as it makes no sense to make the change over point the instant after this point. — Preceding unsigned comment added by 114.77.184.227 (talk) 11:00, 19 July 2011 (UTC)

The United States National Institute of Standards and Technology says you're wrong. Since that is part of the US Department of Commerce, and the Department of Commerce together with the Department of Defense (in effect, the US Naval Observatory and the parts of the US Air Force responsible for the GPS system) are legally responsible for time dissemination in the US, I would say your reasoning is wrong in the US. Jc3s5h (talk) 14:13, 19 July 2011 (UTC)

If one were to see 12:00 a.m. it is vastly more likely to mean midnight than noon. Somehow this de facto interpretation should be clearly reflected in the article. The theoretical musings of one country's authorities notwithstanding. They could be relegated to a footnote. −Woodstone (talk) 14:33, 19 July 2011 (UTC)

Woodstone claims "If one were to see 12:00 a.m. it is vastly more likely to mean midnight than noon." If I were to see 12:00 a.m. and could not reach the author to obtain clarification, I would act on the assumption that it means midnight at the beginning of the date in question. But as a Wikipedia editor, I demand proof in a reliable source if the article is to take that position.

Stated another way, if I worked for an insurance company, and through some error, a policy had been issued that expired at "12:00 am August 1st", and the insured house burned down at 10:00 am August 1st, I wouldn't like my chances if the policy holder sued, contending the policy was in force.

Considering that some of our readers might write statements, such as expiration dates of contracts, or closing times and dates for acceptance of bids, that may be interpreted in a contentious atmosphere, we should not over-emphasize the meaning in casual writing. Jc3s5h (talk) 14:53, 19 July 2011 (UTC)

If there are different sources saying variously that 12:00 a.m. is noon and that 12:00 a.m. is midnight, I'd like you to cite them, Jc3s5h. Otherwise, you are just adding confusion to an already-confusing discussion. --Uncle Ed (talk) 16:41, 1 May 2012 (UTC)

Addressing Jc3s5h six comments back: NIST is finally starting to get it right. See their new spiel about this at http://www.nist.gov/pml/div688/times.cfm#noon. As far as their still insisting that the instant called noon is neither am nor pm makes them fuddy-duddies. Why this slavish adherence to obsolete, ambiguous, medieval definitions of am and pm? Words evolve -- especially after hundreds of years. The 'm' is for "meridies" (hey, who still speaks Latin anyway?!), right? So you'd think noon is when the sun crosses the meridian, which is midday. (In fact, "meridian" comes from "meridies". Make sense, no?) But the sun virtually never crosses the meridian at noon civil time (see Equation of Time). And what is meant by noon? Noon civil time? There was no such thing when am and pm came about. Is it noon local solar time? What a mess. Noon itself is ambiguous! Somehow we got from before/after meridies to before/after midday to before/after noon, which would imply noon local solar time, which would make the original definitions inapplicable to civil time (standard time and DST). One needs to specify whether one means local solar time, civil time, sidereal time, UTC, GMT, IAT, ephemeris time, UT1, UT2, etc. And just what exactly is midday? Certainly not 12:00 civil time when DST is in effect! Noon civil time is not midday. Noon local solar time is. (Additionally, midday sounds more like a period, like evening, than a particular instant in time.) This pretty much destroys the argument in the article. ---- Time is measured by clocks. AM/PM clocks tell you the time, digital or otherwise. The digital ones use 12:00 pm for noon and the 60 seconds following it excluding 12:01 am. Why fuss over an instant? Why insist that digital am/pm clocks (and there may well be more than a billion of them!) are wrong for 2 instants a day? The clock is never going to be exactly right anyway! At the level of instants, no clock is right at any time. ---- Life is simpler if we all just go by what digital clocks show. Why complicate things over an obsolete definition? What good comes from insisting that 12 am and 12 pm are ambiguous or meaningless? To be consistent with medieval definitions? It only makes things more confusing and complicated. It ruins the simplicity of 12 am being midnight and 12 pm being noon. It ruins what would otherwise be a simple, sensible, logical, mathematical (that is, having all columns, including the am/pm column, work with the usual turnover rules) system. While were at it, why not go back to using the archaic definitions of philosophy, namely, physical science and ethics (see http://www.merriam-webster.com/dictionary/philosophy)? If philosophy and other words can evolve away from what are now archaic definitions, why not am and pm? The original definitions are clearly obsolete. It's time to move on. Betaneptune (talk) 21:22, 3 September 2012 (UTC)

More response to Jc3s5h's 14:13, 19 July 2011 (UTC) comment: NIST is responsible for the time, not for am-pm nonsense. Do they send out any time data in the 12-hour format? No! But a recent edition of time.gov allows you to choose between the 12- and 24-hour formats. And with the 12-hour option they violate their own rule! (Well, they now admit it's impractical to implement their rule in digital format, so why even bother with the silly rule in the first place?) The format is most likely coded in the java program; I'd be flabbergasted if they sent am and pm in their transmissions. Aside from that, nothing that they do depends on what am and pm mean at noon or midnight or any other time. The comment above that mentions 12:XX has it right. It's simple and logical and right. (Well, I don't get the part about quanta of light.) As for what should be in the article, it should not take the stand that NIST is right or wrong. It should explain how digital clocks pretty much force the sensible solution I and the 12:XX person have propounded here. I can't believe these NIST people. Have they never programmed a VCR? Think of all the misery they caused by not explaining the way VCR's use time. And with computers now it's at least easier to get it right. As for midnight, many words have multiple meanings and the meaning used must be determined by context. So if I say I want it done by midnight tonight, that means a minute after today's 23:59. If I say it's 10 minutes past midnight, I don't think it's hard to figure out which midnight is meant! If I say you must be done by midnight, Oct 1, that almost always means 1 minute after Oct 1 23:59, though I've yet to see an exception. Yes, in some cases there may be ambiguity, but that's true with a lot of things. Yet midnight remains a useful term in some contexts. Let's ask NIST about driving on the parkway and parking on the driveway. Let's see how they answer that. Betaneptune (talk) 02:40, 4 April 2014 (UTC)

To add another item: How about the terms A.D. and B.C.? If you insist on taking these terms literally, then we don't even know what year it is, as it is not known with any reasonable certainty when Christ was born. Even worse, evidence strongly suggests that the birth could not have happened at the beginning of A.D. 1. This would mean that we are presently numbering our years incorrectly. And how do we deal with the fact that the birth is supposed to be on December 25? Of which year? --- It is no less silly to take the original meanings of a.m. and p.m. literally. For the year, we just continue with what we do now. For the time, 12:00 a.m. is midnight and 12:00 pm is noon. It's as simple as that. Betaneptune (talk) 02:23, 10 May 2014 (UTC)

Yes, you are correct that it is just convention, but the difference is that almost everyone, world-wide, agrees on the year number, though some use CE instead of AD either for the reason you mention or because they object to the use of the abbreviation of the Latin word for Lord (and some others prefer to use a different starting date but recognise CE). In the case of a.m. and p.m. there are many people who object to the usage of either for noon, and avoid this usage, and there are many others who remain confused despite our explanatory article. Dbfirs 16:00, 10 May 2014 (UTC)

12 vs. 24 hour clock dial and centuries

The article contains this paragraph:

During the 15th and 16th centuries, the 12-hour analog dial and time system gradually became established as standard throughout Northern Europe for general public use. The 24-hour analog dial was reserved for more specialized applications, such as astronomical clocks and chronometers, and timetables, especially for railway and airline travel.

Neither railways nor airlines existed in the 15th and 16th centuries. This paragraph needs to be rewritten to make sense.

ZeroXero (talk) 03:33, 31 March 2015 (UTC)

Good point. I'll adjust the paragraph. Dbfirs 07:41, 31 March 2015 (UTC)

Is Midnight 12 am or 12 pm?

Americans have style guides that state 12 pm is Noon. Where I grew up in Kenya, 12 pm was midnight. I've asked many people that I know in the UK, South Africa, Kenya, Australia what time of day 12 pm was? Every one of them said midnight. How do we prove this when there is no "style" guide? Government or standardisation organisations in English speaking countries dictate use of the 24 hour clock. So we're left with what people in general might express online or in conversation.

Here is an extract from Trip Advisor feedback on hotels, http://www.tripadvisor.com/Hotels-g1940497-Muscat_Muscat_Governorate-Hotels.html, the respondent states: "I prefer to stay on the Club floors (4th and 5th floors) where the club lounge remains open till 11 or 12 pm! A relaxing place to hang out after a long day". What I take from this is that this person uses 12 pm as the end of the day, as would I. Other examples would be appreciated. Avi8tor (talk) 22:21, 19 June 2014 (UTC)

Because of this confusion, the best advice is to avoid using a.m. and p.m. after "12". Just use "noon" and "midnight". It seems that the majority, world-wide, use 12 p.m. to mean noon, then 12:01 p.m. follows on, but I agree with you that there is no universality about this convention. I've never used it. Dbfirs 06:34, 20 June 2014 (UTC)

Certainly on computers or digital clocks 12:00 p.m. is always noon, never midnight. −Woodstone (talk) 16:39, 20 June 2014 (UTC)

There is an important difference between a static time, such as time written on a piece of paper, and the dynamic display of a clock, especially a digital clock. If we imagine that an ideal digital clock that's perfectly accurate and that it only displays hours and minutes, for an infinitesimally short time it displays whatever notation the clock designer things is appropriate for noon, either 12:00 AM or 12:00 PM. But the duration of that display is 0 seconds, so it cannot be seen. Then it is afternoon, and the clock displays 12:00 PM until a minute has passed, and then it displays 12:01 PM. Of course a practical clock will ignore the question of what the correct display would be for noon, and only display the correct notation for afternoon.

If it happens to be an alarm clock, then the issue of the correct notation for noon and midnight comes into play when setting the alarm. Jc3s5h (talk) 21:27, 20 June 2014 (UTC)

The disambiguation of 12AM and 12PM provided in the article is useful, but might I suggest that we add the standards used by computing? 12AM has a fuzzy meaning in english, but it probably has a very specific meaning in Unix and Windows (And I hope the same one...)70.90.204.42 (talk) 12:24, 28 May 2015 (UTC)

Wikipedia - from a basic intelligence level you and or the American and Canadian International Convention is illogical and wrong!

00.01am is a minute past midnight - 11 hours and 59 minutes before 12 Noon.

12.01am doesn't exist because it is actually 00:01am; but 12.01pm (afternoon) does when using the 12 hour clock.

It is 59 minutes before 1pm.

Having reached the Twelfth division, the units return to zero, so technically 12:01 does not exist - especially just after Midnight and 12:01 only exists just after Noon in the 24 hour clock system.

Therefore the use of am and pm with the number 12 should be avoided at all costs, if confusion is also to be avoided.

Wikipedia is always right?

.....And all people should accept any and all absolutely absurd and confusing American and Canadian conventions which are 11 hours and 59 minutes adrift/apart.

Key Facts:-

example:- News Story reporting a sighting of a missing child.

11.59pm is 1 minute before midnight - so it's completely illogical that the missing kid was last seen between 11:00am and 12pm - so he was in the same place for 13 hours then? 13 hours or 1 hour in one place - I think most probably 1 hour between 11am and noon but the police didn't correct or clarify their tweet. Nor did they quote Wikipedia with all quotes from American and Canadian Sources.

....12pm is 11 hours and 59 minutes later!?

Similarly 12:01pm is 1 minute after 12 Noon and not 1 minute after Midnight - that is 00:01am

If you, the Americans, Canadians and Wikipedia are all right then the kid was seen/observed for 13 hours!

Think we need to use British English and sensibly avoid using the am or pm suffixes; but instead use the terms Noon, Mid-day or Midday and Mid-Night or Midnight.

It is therefore well advised to drop the use of 12am or pm because there is confusion and people can easily be 11 hours and 59 minutes early or equally, 12 hours and a minute late - or is it the other way round?

More intelligent to say 12 noon, Mid-day/Midday and use 12 mid-night/Midnight or just midnight for 24:00 if not sensibly using the 24 hour clock.

Digital Clocks need correctly reprogramming to avoid 12am and 12pm and convention needs amending to apply colloquial and general terms used in the every day universally accepted British English Language.

The difference is as plain to see as Night and Day!

Conclusion regarding the Time and Clock Convention.

General Analogue meter reading conventions.

When reading an analogue gas or electric meter - or any meter for that matter, it is read backwards and not forwards. That is to say that a Seven stays a Seven until the next unit/dial zero has passed through zero, which then simultaneously changes the Seven to the next whole number, namely an Eight. To read the Seven and Three quarters as an Eight for the whole set of dials would give a dramatically inflated reading and subsequently a very very high Gas or Electric bill.

A clock is a measuring device or meter and so therefore to read it accurately and correctly the same conventions need to be applied. Using this principal, in the case of a clock and time it is still in the Eleventh hour until it actually passes the twelve. There is no Twelfth hour time period and so therefore it stays am until precisely Twelve o'clock plus a fraction of a Nano second. When using a twelve hour system the next unit after Twelve is Zero and Zero plus an infinitely small proportion of a Nano second is 00:00:00:01pm. So am does not become pm until a very small fraction of time after Twelve o'clock and therefore up until the change to pm the time actually still remains am. Incorrectly reading forwards causes an increase of Eleven hours Fifty Nine Minutes and a large number of Nano seconds. The logical and analytical difference when explained correctly in this way is as plain to see as Night and Day!

A comment on the Twelve Hour Clock.

It is very important to remember that a Twelve Hour Clock has only Two divisions of Twelve hour periods and that the Thirteenth Hour does not exist. An am time period ends at 12:00 and a pm time period starts immediately the time has passed a split Nano second after the Twelfth hour and begins at zero. So technically speaking there is no true time of Twelve Twenty in the use of the Twelve Hour Clock for example. It is a misnomer. Twelve Twenty does exist, however, in the Twenty Four Hour Clock.

It is very important to remember that a Twelve Hour Clock has only Two divisions of Twelve hour periods and that the Thirteenth Hour does not exist. An am time period ends at 12:00 and a pm time period starts immediately the time has passed a split Nano second after the Twelfth hour and begins at zero. So technically speaking there is no true time of Twelve Twenty in the use of the Twelve Hour Clock for example. It is a misnomer.

Twelve Twenty does exist, however, in the Twenty Four Hour Clock.

HigherIntelligence. — Preceding unsigned comment added by HigherIntelligence (talk • contribs) 13:32, 21 June 2014 (UTC)

This is not an American versus British issue. The use of "12 p.m." instead of saying 12 noon seems to be common world-wide. I agree with you that it is best avoided, but we have to accept the world as it is, including accepting the figure 12, not zero, at the top of our clocks. (_{Posting your opinion on Wikipedia is not going to change the world, however high your intelligence.}) Dbfirs 17:47, 21 June 2014 (UTC)

HigherIntelligence: This is a wikipedia talk page for improving the article, not a forum for generalized discussion for your (somewhat logical, I will admit) feelings about how time and clock conventions are used in various places. Your comments are completely off topic for this talk page. Utter wankery is a not a demonstration of higher intelligence. If you have suggestions for improving the article, by all means advance them. Hating the way that the world works and complaining about it are not a legitimate use of Wikipedia talk pages, sorry. (Reply at 04:29 on March 31, 2015‎ by User:ZeroXero(talk))