September in Nijmegen averages a daily high of 20.4°C with nights around 10.2°C. Expect roughly 12.9 wet days totalling 66.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Nijmegen is May–September.
Based on KLEVE, GM (18.9km), 1995–2024. 30 years of September data.