September in Stockholm averages a daily high of 17.2°C with nights around 10.5°C. Expect roughly 12.5 wet days totalling 90.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Stockholm is June–August.
Based on STOCKHOLM A, SW (1.3km), 1995–2024. 28 years of September data.