| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Record high °F (°C) | 63 (17) |
73 (23) |
81 (27) |
93 (34) |
102 (39) |
111 (44) |
114 (46) |
109 (43) |
105 (41) |
95 (35) |
79 (26) |
66 (19) |
114 (46) |
| Mean maximum °F (°C) | 46.7 (8.2) |
49.9 (9.9) |
66.7 (19.3) |
80.2 (26.8) |
87.1 (30.6) |
93.2 (34.0) |
98.3 (36.8) |
98.2 (36.8) |
93.0 (33.9) |
82.1 (27.8) |
63.9 (17.7) |
49.4 (9.7) |
101.4 (38.6) |
| Mean daily maximum °F (°C) | 23.2 (−4.9) |
27.8 (−2.3) |
41.0 (5.0) |
56.0 (13.3) |
68.3 (20.2) |
77.9 (25.5) |
84.7 (29.3) |
83.5 (28.6) |
73.4 (23.0) |
57.1 (13.9) |
40.6 (4.8) |
27.7 (−2.4) |
55.1 (12.8) |
| Daily mean °F (°C) | 12.8 (−10.7) |
17.5 (−8.1) |
30.1 (−1.1) |
43.2 (6.2) |
55.3 (12.9) |
65.4 (18.6) |
71.3 (21.8) |
69.6 (20.9) |
59.7 (15.4) |
44.8 (7.1) |
29.9 (−1.2) |
17.9 (−7.8) |
43.1 (6.2) |
| Mean daily minimum °F (°C) | 2.4 (−16.4) |
7.2 (−13.8) |
19.1 (−7.2) |
30.4 (−0.9) |
42.4 (5.8) |
52.9 (11.6) |
57.9 (14.4) |
55.7 (13.2) |
45.9 (7.7) |
32.6 (0.3) |
19.1 (−7.2) |
8.1 (−13.3) |
31.1 (−0.5) |
| Mean minimum °F (°C) | −23.8 (−31.0) |
−17.6 (−27.6) |
−4.7 (−20.4) |
13.4 (−10.3) |
26.9 (−2.8) |
39.7 (4.3) |
46.2 (7.9) |
43.3 (6.3) |
29.8 (−1.2) |
15.9 (−8.9) |
−1.0 (−18.3) |
−16.0 (−26.7) |
−27.9 (−33.3) |
| Record low °F (°C) | −45 (−43) |
−45 (−43) |
−36 (−38) |
−12 (−24) |
13 (−11) |
30 (−1) |
32 (0) |
32 (0) |
10 (−12) |
−10 (−23) |
−30 (−34) |
−43 (−42) |
−45 (−43) |
| Average precipitation inches (mm) | 0.48 (12) |
0.52 (13) |
0.84 (21) |
1.34 (34) |
2.50 (64) |
3.36 (85) |
3.07 (78) |
2.50 (64) |
1.72 (44) |
1.43 (36) |
0.69 (18) |
0.60 (15) |
19.05 (484) |
| Average snowfall inches (cm) | 8.9 (23) |
7.5 (19) |
8.5 (22) |
4.6 (12) |
0.4 (1.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
2.5 (6.4) |
8.0 (20) |
10.1 (26) |
50.5 (128) |
| Average extreme snow depth inches (cm) | 8.0 (20) |
7.0 (18) |
5.8 (15) |
3.5 (8.9) |
0.2 (0.51) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
1.3 (3.3) |
4.4 (11) |
6.3 (16) |
11.5 (29) |
| Average precipitation days (≥ 0.01 in) | 7.8 | 7.9 | 7.5 | 8.1 | 10.4 | 11.6 | 9.7 | 8.0 | 7.3 | 7.2 | 6.6 | 7.7 | 99.8 |
| Average snowy days (≥ 0.1 in) | 9.9 | 8.7 | 6.3 | 2.7 | 0.4 | 0.0 | 0.0 | 0.0 | 0.0 | 2.5 | 8.0 | 10.1 | 44.6 |
| Average relative humidity (%) | 71.3 | 72.4 | 69.9 | 61.8 | 60.1 | 65.0 | 61.8 | 60.6 | 63.7 | 63.8 | 72.0 | 74.5 | 66.4 |
| Average dew point °F (°C) | 2.3 (−16.5) |
8.6 (−13.0) |
18.9 (−7.3) |
28.6 (−1.9) |
39.6 (4.2) |
50.5 (10.3) |
54.9 (12.7) |
52.0 (11.1) |
42.4 (5.8) |
32.2 (0.1) |
19.8 (−6.8) |
7.5 (−13.6) |
29.8 (−1.2) |
| Mean monthly sunshine hours | 149.4 | 153.5 | 222.3 | 244.3 | 296.1 | 318.1 | 354.6 | 316.2 | 245.9 | 191.7 | 122.6 | 122.9 | 2,737.6 |
| Percent possible sunshine | 53 | 53 | 60 | 60 | 64 | 67 | 74 | 72 | 65 | 57 | 43 | 46 | 61 |
| Average ultraviolet index | 0.8 | 1.5 | 2.9 | 4.7 | 6.3 | 7.5 | 7.9 | 6.7 | 4.6 | 2.4 | 1.1 | 0.8 | 3.9 |
| Source 1: NOAA (relative humidity and sun 1961–1990)[1][2][3] | |||||||||||||
| Source 2: UV Index Today (1995 to 2022)[4] | |||||||||||||
- ^ Mean monthly maxima and minima (i.e. the highest and lowest temperature readings during an entire month or year) calculated based on data at said location from 1991 to 2020.
- ^ Records for Bismarck have been kept at the Bismarck Municipal Airport since January 1948 and at an undisclosed location from October 1874 to December 1947.
- ^ "NOWData – NOAA Online Weather Data". National Oceanic and Atmospheric Administration. Retrieved September 16, 2021.
- ^ "Station Name: ND BISMARCK". U.S. Climate Normals 2020: U.S. Monthly Climate Normals (1991–2020). National Oceanic and Atmospheric Administration. Retrieved June 5, 2021.
- ^ "WMO Climate Normals for BISMARCK/MUNICIPAL, ND 1961–1990". National Oceanic and Atmospheric Administration. Retrieved March 10, 2014.
- ^ "Historical UV Index Data - Bismarck, ND". UV Index Today. Retrieved April 22, 2023.