March in Ottawa South 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 South is May–September.
Based on OTTAWA CDA, ON CA (2.5km), 1995–2024. 29 years of March data.