| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.1° | -0.7° | 60.3mm | 15 | 18 |
| February | 7° | -0.4° | 57.2mm | 13.5 | 28 |
| March | 11.5° | 1.6° | 60.4mm | 12.8 | 47 |
| April | 16.7° | 4.7° | 48mm | 11.1 | 67 |
| May | 20.6° | 8.7° | 80.9mm | 12.9 | 74 |
| June | 25° | 12.3° | 72.7mm | 11.8 | 76 |
| July | 26.7° | 13.9° | 83.4mm | 13 | 74 |
| August | 25.8° | 13.5° | 75.9mm | 12 | 76 |
| September | 21.7° | 10° | 59.3mm | 10.6 | 79 |
| October | 16.2° | 6.6° | 71.2mm | 12.4 | 63 |
| November | 9.5° | 2.8° | 66.3mm | 13.7 | 39 |
| December | 6° | 0.4° | 73.1mm | 16.1 | 23 |
January in Heilbronn averages a daily high of 5.1°C with nights around -0.7°C. Expect roughly 15 wet days totalling 60.3mm. A hard month to visit for comfort alone.
February in Heilbronn averages a daily high of 7°C with nights around -0.4°C. Expect roughly 13.5 wet days totalling 57.2mm. A hard month to visit for comfort alone.
March in Heilbronn averages a daily high of 11.5°C with nights around 1.6°C. Expect roughly 12.8 wet days totalling 60.4mm. Demanding conditions — pack for it and plan indoor options.
April in Heilbronn averages a daily high of 16.7°C with nights around 4.7°C. Expect roughly 11.1 wet days totalling 48mm. Generally workable, with some weather to plan around.
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.
June in Heilbronn averages a daily high of 25°C with nights around 12.3°C. Expect roughly 11.8 wet days totalling 72.7mm. Comfortable conditions for being outdoors all day.
July in Heilbronn averages a daily high of 26.7°C with nights around 13.9°C. Expect roughly 13 wet days totalling 83.4mm. Generally workable, with some weather to plan around.
August in Heilbronn averages a daily high of 25.8°C with nights around 13.5°C. Expect roughly 12 wet days totalling 75.9mm. Comfortable conditions for being outdoors all day.
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.
October in Heilbronn averages a daily high of 16.2°C with nights around 6.6°C. Expect roughly 12.4 wet days totalling 71.2mm. Generally workable, with some weather to plan around.
November in Heilbronn averages a daily high of 9.5°C with nights around 2.8°C. Expect roughly 13.7 wet days totalling 66.3mm. Demanding conditions — pack for it and plan indoor options.
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.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Heilbronn peaks at 79.
Based on 30 years of records, May–September scores highest for comfort in Heilbronn, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 26.7°C.
July is the wettest, averaging 83.4mm of rain across roughly 13 wet days.
January is the coolest month, with average daily highs around 5.1°C.