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.
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 August data.