July in Mainz averages a daily high of 25.9°C with nights around 15.3°C. Expect roughly 11.5 wet days totalling 62.7mm. 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 July data.