May in Heilbronn averages a daily high of 20.6°C with nights around 8.7°C. Expect roughly 12.9 wet days totalling 80.9mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Heilbronn is May–September.
Based on OBERSULM WILLSBACH, GM (9.7km), 1995–2024. 20 years of May data.