May in Belleville averages a daily high of 19.4°C with nights around 8.8°C. Expect roughly 11.5 wet days totalling 76.1mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Belleville is May–September.
Based on BELLEVILLE, ON CA (2.3km), 1995–2024. 27 years of May data.