September in Västerås averages a daily high of 16.8°C with nights around 8.6°C. Expect roughly 10.5 wet days totalling 45.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Västerås is June–September.
Based on VASTERAS HASSLO, SW (5.2km), 1995–2024. 27 years of September data.