December in Västerås averages a daily high of 1.3°C with nights around -3.5°C. Expect roughly 15 wet days totalling 51.9mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Västerås is June–September.
Based on VASTERAS HASSLO, SW (5.2km), 1995–2024. 29 years of December data.