December in Iserlohn averages a daily high of 4.3°C with nights around -0.1°C. Expect roughly 19.5 wet days totalling 115.3mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Iserlohn is June–September.
Based on LUDENSCHEID, GM (14.9km), 1995–2024. 30 years of December data.