May in Grand Forks averages a daily high of 19.1°C with nights around 6.4°C. Expect roughly 11.2 wet days totalling 80.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Grand Forks is May–September.
Based on GRAND FORKS UNIVERSITY NWS, ND US (4.8km), 1995–2024. 29 years of May data.