September in Richmond Hill averages a daily high of 24.8°C with nights around 16.6°C. Expect roughly 8.1 wet days totalling 95.5mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Richmond Hill is August–October.
Based on JFK INTERNATIONAL AIRPORT, NY US (8.8km), 1995–2024. 30 years of September data.