September in Gronau averages a daily high of 19.7°C with nights around 9.2°C. Expect roughly 12 wet days totalling 63mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Gronau is May–September.
Based on TWENTHE, NL (11.3km), 1995–2024. 30 years of September data.