December in Heilbronn averages a daily high of 6°C with nights around 0.4°C. Expect roughly 16.1 wet days totalling 73.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Heilbronn is May–September.
Based on OBERSULM WILLSBACH, GM (9.7km), 1995–2024. 21 years of December data.