December in Dubuque averages a daily high of 0.7°C with nights around -7.4°C. Expect roughly 8.8 wet days totalling 44.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Dubuque is August–September.
Based on DUBUQUE LOCK AND DAM 11, IA US (4.6km), 1995–2024. 30 years of December data.