September in Turku averages a daily high of 16.5°C with nights around 8.8°C. Expect roughly 11 wet days totalling 55.3mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Turku is June–August.
Based on TURKU ARTUKAINEN, FI (4.8km), 1995–2024. 22 years of September data.