May in St. Louis averages a daily high of 25.2°C with nights around 15.1°C. Expect roughly 11.8 wet days totalling 125.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit St. Louis is April–May.
Based on ST LOUIS SCIENCE CENTER, MO US (6.3km), 1995–2024. 17 years of May data.