September in Roskilde averages a daily high of 17.8°C with nights around 12.8°C. Expect roughly 9.8 wet days totalling 45.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Roskilde is June–September.
Based on FALSTERBO, SW (54.9km), 1995–2024. 30 years of September data.