September in Gatineau averages a daily high of 21°C with nights around 9.6°C. Expect roughly 10.8 wet days totalling 92.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Gatineau is May–September.
Based on CHELSEA, QC CA (7.7km), 1995–2024. 23 years of September data.