Click on a day for an hourly weather forecast
The temperatures in Bismarck in September are comfortable with low of 12°C and and high up to 23°C.
You can expect about 3 to 8 days of rain in Bismarck during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Bismarck in September 2025.
If you’re planning to visit Bismarck in the near future, we highly recommend that you review the 14 day weather forecast for Bismarck before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | -7° / -14° | 4 | 11 | 16 | 31 mm | Awful | Bismarck in January |
| February | -6° / -14° | 3 | 9 | 16 | 31 mm | Awful | Bismarck in February |
| March | 3° / -4° | 6 | 12 | 13 | 53 mm | Awful | Bismarck in March |
| April | 10° / 1° | 6 | 17 | 7 | 75 mm | Bad | Bismarck in April |
| May | 18° / 8° | 8 | 22 | 1 | 122 mm | Ok | Bismarck in May |
| June | 25° / 14° | 7 | 23 | 0 | 132 mm | Good | Bismarck in June |
| July | 29° / 17° | 4 | 27 | 0 | 84 mm | Good | Bismarck in July |
| August | 28° / 16° | 4 | 27 | 0 | 77 mm | Perfect | Bismarck in August |
| September | 23° / 12° | 4 | 26 | 0 | 63 mm | Perfect | Bismarck in September |
| October | 12° / 4° | 4 | 23 | 4 | 60 mm | Bad | Bismarck in October |
| November | 4° / -3° | 3 | 18 | 9 | 24 mm | Awful | Bismarck in November |
| December | -5° / -11° | 3 | 11 | 16 | 40 mm | Awful | Bismarck in December |