August in Saint Joseph averages a daily high of 30.2°C with nights around 18.1°C. Expect roughly 9.7 wet days totalling 103.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Saint Joseph is April–May.
Based on ST JOSEPH ROSECRANS MEMORIAL AIRPORT, MO US (5.4km), 1995–2024. 27 years of August data.