| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -4.5° | -15.8° | 12.3mm | 7.8 | 14 |
| February | -2.2° | -13.9° | 13.4mm | 7.7 | 15 |
| March | 4.7° | -7.6° | 21.8mm | 7.4 | 22 |
| April | 13° | -1° | 36.2mm | 8.5 | 56 |
| May | 20.1° | 5.8° | 64.5mm | 10.8 | 78 |
| June | 26° | 11.9° | 82.4mm | 11.4 | 77 |
| July | 29.8° | 15° | 70.1mm | 9 | 71 |
| August | 28.8° | 13.6° | 66.4mm | 8 | 77 |
| September | 23.6° | 8.3° | 40.4mm | 7.2 | 86 |
| October | 14.2° | 0.7° | 36.3mm | 7.5 | 64 |
| November | 5.2° | -7° | 16.7mm | 6.2 | 27 |
| December | -2.3° | -13.1° | 16.7mm | 8.1 | 14 |
January in Bismarck averages a daily high of -4.5°C with nights around -15.8°C. Expect roughly 7.8 wet days totalling 12.3mm. A hard month to visit for comfort alone.
February in Bismarck averages a daily high of -2.2°C with nights around -13.9°C. Expect roughly 7.7 wet days totalling 13.4mm. A hard month to visit for comfort alone.
March in Bismarck averages a daily high of 4.7°C with nights around -7.6°C. Expect roughly 7.4 wet days totalling 21.8mm. A hard month to visit for comfort alone.
April in Bismarck averages a daily high of 13°C with nights around -1°C. Expect roughly 8.5 wet days totalling 36.2mm. Generally workable, with some weather to plan around.
May in Bismarck averages a daily high of 20.1°C with nights around 5.8°C. Expect roughly 10.8 wet days totalling 64.5mm. Comfortable conditions for being outdoors all day.
June in Bismarck averages a daily high of 26°C with nights around 11.9°C. Expect roughly 11.4 wet days totalling 82.4mm. Comfortable conditions for being outdoors all day.
July in Bismarck averages a daily high of 29.8°C with nights around 15°C. Expect roughly 9 wet days totalling 70.1mm. Generally workable, with some weather to plan around.
August in Bismarck averages a daily high of 28.8°C with nights around 13.6°C. Expect roughly 8 wet days totalling 66.4mm. Comfortable conditions for being outdoors all day.
September in Bismarck averages a daily high of 23.6°C with nights around 8.3°C. Expect roughly 7.2 wet days totalling 40.4mm. Comfortable conditions for being outdoors all day.
October in Bismarck averages a daily high of 14.2°C with nights around 0.7°C. Expect roughly 7.5 wet days totalling 36.3mm. Generally workable, with some weather to plan around.
November in Bismarck averages a daily high of 5.2°C with nights around -7°C. Expect roughly 6.2 wet days totalling 16.7mm. A hard month to visit for comfort alone.
December in Bismarck averages a daily high of -2.3°C with nights around -13.1°C. Expect roughly 8.1 wet days totalling 16.7mm. A hard month to visit for comfort alone.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Bismarck peaks at 86.
Based on 30 years of records, May scores highest for comfort in Bismarck, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 29.8°C.
June is the wettest, averaging 82.4mm of rain across roughly 11.4 wet days.
January is the coolest month, with average daily highs around -4.5°C.