December in Gronau averages a daily high of 5.9°C with nights around 0.9°C. Expect roughly 16.7 wet days totalling 73.7mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Gronau is May–September.
Based on TWENTHE, NL (11.3km), 1995–2024. 30 years of December data.