May in Niagara Falls averages a daily high of 20.3°C with nights around 8.3°C. Expect roughly 12.4 wet days totalling 76mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Niagara Falls is May–September.
Based on NIAGARA FALLS, NY US (7.8km), 1995–2024. 25 years of May data.