December in Belleville averages a daily high of 1.9°C with nights around -5.6°C. Expect roughly 13.2 wet days totalling 70.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Belleville is May–September.
Based on BELLEVILLE, ON CA (2.3km), 1995–2024. 26 years of December data.