May in Montréal averages a daily high of 19.3°C with nights around 9.6°C. Expect roughly 12.1 wet days totalling 84.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Montréal is May–September.
Based on MCTAVISH, QC CA (1km), 1995–2024. 27 years of May data.