May in Welland averages a daily high of 19.9°C with nights around 7.7°C. Expect roughly 11.3 wet days totalling 69.5mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Welland is May–September.
Based on WELLAND PELHAM, ON CA (7.1km), 1995–2024. 18 years of May data.