October in Mainz averages a daily high of 14.8°C with nights around 7.7°C. Expect roughly 11.6 wet days totalling 51.5mm. Generally workable, with some weather to plan around.
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 October data.