Climate averages 1991–2020
Bismarck weather
in August.
A warm, moderately wet month: the 2nd warmest and the 9th driest of the year. Meets the pleasant-weather rule
Long-term climate patterns, not a forecast for a particular trip.
August is a warm month in Bismarck: daytime highs average 26.9°C and nights cool to about 15.9°C. By daytime temperature it is the 2nd warmest of the 12 months.
Expect about 58 mm of rain on roughly 7 days, which makes August a moderately wet month (the 9th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 13 min on an average August day.
The nearest other city in this atlas is Fargo (304 km away). In August its highs average 25.9°C, 1.0°C cooler than Bismarck, with 82 mm of rain.
Among the 498 cities listed in the United States, Bismarck ranks joint 384th of 498 for the warmest August highs and joint 211th of 498 for the driest August (rainfall, lowest first). The mean August high of those 498 cities is 29.9°C; Bismarck is 3.1°C cooler than that mean.
From August to September, average highs fall by 5.4°C to 21.4°C, and monthly rainfall falls from 58 mm to 46 mm.
The annual picture
August in context
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Bismarck climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | -5.9°C-15.1°C | -15.1°C | 16 | 4.5 | 9.09 h |
| February | -2.9°C-12.5°C | -12.5°C | 18 | 4.5 | 10.310 h |
| March | 3.8°C-6.6°C | -6.6°C | 26 | 5.0 | 11.912 h |
| April | 11.4°C-0.1°C | -0.1°C | 46 | 7.5 | 13.614 h |
| May | 18.4°C7.3°C | 7.3°C | 73 | 9.8 | 15.015 h |
| June | 23.6°C13.3°C | 13.3°C | 96 | 10.9 | 15.816 h |
| July | 27.3°C16.7°C | 16.7°C | 77 | 9.7 | 15.515 h |
| August, selected | 26.9°C15.9°C | 15.9°C | 58 | 7.4 | 14.214 h |
| September | 21.4°C10.9°C | 10.9°C | 46 | 6.5 | 12.613 h |
| October | 12.7°C3.3°C | 3.3°C | 45 | 6.5 | 10.911 h |
| November | 3.6°C-4.6°C | -4.6°C | 21 | 4.1 | 9.49 h |
| December | -3.4°C-11.4°C | -11.4°C | 18 | 4.4 | 8.69 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
August in nearby cities
- Fargo in AugustUnited States · 304 kmHigh 25.9°C · Low 16.1°C · 82 mm rain
- Rapid City in AugustUnited States · 358 kmHigh 28.2°C · Low 16.1°C · 60 mm rain
- Winnipeg in AugustCanada · 435 kmHigh 24.1°C · Low 14.4°C · 76 mm rain
- Sioux Falls in AugustUnited States · 482 kmHigh 26.6°C · Low 17.1°C · 85 mm rain
- Regina in AugustCanada · 493 kmHigh 24.0°C · Low 13.2°C · 61 mm rain
- Sioux City in AugustUnited States · 591 kmHigh 27.5°C · Low 18.1°C · 98 mm rain
- Plymouth, United States in AugustUnited States · 601 kmHigh 25.9°C · Low 17.5°C · 99 mm rain
- Billings in AugustUnited States · 603 kmHigh 30.0°C · Low 15.8°C · 18 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Bismarck) is explained once on the Bismarck year overview and on the Sources, method and limits page.