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.
Across the year, the best time to visit Bismarck is May.
Based on BISMARCK MUNICIPAL AIRPORT, ND US (4.5km), 1995–2024. 30 years of December data.