September in Heilbronn averages a daily high of 21.7°C with nights around 10°C. Expect roughly 10.6 wet days totalling 59.3mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Heilbronn is May–September.
Based on OBERSULM WILLSBACH, GM (9.7km), 1995–2024. 21 years of September data.