July in Waukegan averages a daily high of 27.2°C with nights around 16.8°C. Expect roughly 10.2 wet days totalling 97mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Waukegan is May–September.
Based on CHICAGO WAUKEGAN REGIONAL AIRPORT, IL US (7.1km), 1995–2024. 24 years of July data.