May in Ames averages a daily high of 22.4°C with nights around 9.9°C. Expect roughly 13.4 wet days totalling 138.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Ames is September.
Based on AMES MUNICIPAL AIRPORT, IA US (4.9km), 1995–2024. 28 years of May data.