March in Ottawa averages a daily high of 3.1°C with nights around -6.2°C. Expect roughly 10.8 wet days totalling 60.4mm. A hard month to visit for comfort alone.
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 March data.