January in Sundsvall averages a daily high of -1.6°C with nights around -8.9°C. Expect roughly 12.8 wet days totalling 59.6mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Sundsvall is June–August.
Based on SIDSJO, SW (1.5km), 1995–2024. 13 years of January data.