September in Amersfoort averages a daily high of 19.8°C with nights around 10.1°C. Expect roughly 12.4 wet days totalling 76.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Amersfoort is May–September.
Based on DE BILT, NL (15.5km), 1995–2024. 30 years of September data.