August in Deventer averages a daily high of 23°C with nights around 12.1°C. Expect roughly 13.3 wet days totalling 79.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Deventer is May–September.
Based on HEINO, NL (20.9km), 1995–2024. 30 years of August data.