April in Siegen averages a daily high of 15.2°C with nights around 2.6°C. Expect roughly 11.5 wet days totalling 46.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Siegen is May–September.
Based on DILLENBURG, GM (23.1km), 1995–2024. 28 years of April data.