August in Wheaton averages a daily high of 27.9°C with nights around 16.2°C. Expect roughly 10.6 wet days totalling 83mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Wheaton is May–June.
Based on CHICAGO WEST CHICAGO DUPAGE AIRPORT, IL US (12.4km), 1995–2024. 28 years of August data.