January in Sarnia averages a daily high of 0°C with nights around -7°C. Expect roughly 14.1 wet days totalling 61.6mm. 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. 28 years of January data.