January in Oshawa averages a daily high of -0.7°C with nights around -8.1°C. Expect roughly 12.5 wet days totalling 73.2mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Oshawa is June–September.
Based on OSHAWA WPCP, ON CA (3.9km), 1995–2024. 23 years of January data.