August in Mainz averages a daily high of 25.7°C with nights around 15°C. Expect roughly 10.7 wet days totalling 52.2mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Mainz is May–September.
Based on MAINZ LERCHENBERG ZDF, GM (5.1km), 1995–2024. 29 years of August data.