August in Waukegan averages a daily high of 26.6°C with nights around 16.4°C. Expect roughly 11.7 wet days totalling 88.3mm. 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. 25 years of August data.