September in Iserlohn averages a daily high of 18°C with nights around 9.3°C. Expect roughly 13.4 wet days totalling 89mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Iserlohn is June–September.
Based on LUDENSCHEID, GM (14.9km), 1995–2024. 30 years of September data.