October in Ottawa averages a daily high of 13.8°C with nights around 4.8°C. Expect roughly 13.8 wet days totalling 91.9mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Ottawa is May–September.
Based on OTTAWA CDA, ON CA (3.4km), 1995–2024. 29 years of October data.