April in Waukegan averages a daily high of 13.2°C with nights around 2.5°C. Expect roughly 12 wet days totalling 89.4mm. Demanding conditions — pack for it and plan indoor options.
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 April data.