September in Dortmund averages a daily high of 20.2°C with nights around 10.2°C. Expect roughly 11.3 wet days totalling 60.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Dortmund is May–September.
Based on BOCHUM, GM (14.1km), 1995–2024. 13 years of September data.