December in Waukegan averages a daily high of 2.3°C with nights around -5.5°C. Expect roughly 9.2 wet days totalling 52.3mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Waukegan is May–September.
Based on CHICAGO WAUKEGAN REGIONAL AIRPORT, IL US (7.1km), 1995–2024. 26 years of December data.