May in Champaign averages a daily high of 23.4°C with nights around 11.4°C. Expect roughly 13.8 wet days totalling 119.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Champaign is September.
Based on CHAMPAIGN 3 S, IL US (3.6km), 1995–2024. 29 years of May data.