March in Sarnia averages a daily high of 6.2°C with nights around -2.4°C. Expect roughly 10.1 wet days totalling 59.5mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Sarnia is May–September.
Based on PORT HURON, MI US (1.3km), 1995–2024. 29 years of March data.