Climate averages 1991–2020
Heidelberg, Germany weather
in September.
A mild, moderately wet month: the 4th warmest and the 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Heidelberg, Germany: daytime highs average 20.3°C and nights cool to about 11.7°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 66 mm of rain on roughly 10 days, which makes September a moderately wet month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 40 min on an average September day.
The nearest other city in this atlas is Mannheim (19 km away). In September its highs average 20.4°C, about as warm as Heidelberg, Germany, with 55 mm of rain.
Among the 120 cities listed in Germany, Heidelberg, Germany ranks 4th of 120 for the warmest September highs and joint 69th of 120 for the driest September (rainfall, lowest first). The mean September high of those 120 cities is 18.8°C; Heidelberg, Germany is 1.5°C warmer than that mean.
From September to October, average highs fall by 5.2°C to 15.1°C, and monthly rainfall rises from 66 mm to 72 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Heidelberg, Germany climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 5.0°C-0.4°C | -0.4°C | 80 | 13.1 | 8.79 h |
| February | 6.6°C-0.2°C | -0.2°C | 67 | 11.2 | 10.110 h |
| March | 10.8°C2.4°C | 2.4°C | 75 | 12.5 | 11.912 h |
| April | 15.4°C5.5°C | 5.5°C | 54 | 11.1 | 13.714 h |
| May | 19.3°C9.9°C | 9.9°C | 79 | 12.7 | 15.315 h |
| June | 22.7°C13.4°C | 13.4°C | 68 | 11.9 | 16.216 h |
| July | 24.9°C15.6°C | 15.6°C | 73 | 12.3 | 15.816 h |
| August | 24.9°C15.5°C | 15.5°C | 60 | 10.0 | 14.414 h |
| September, selected | 20.3°C11.7°C | 11.7°C | 66 | 10.0 | 12.713 h |
| October | 15.1°C7.9°C | 7.9°C | 72 | 12.1 | 10.811 h |
| November | 9.2°C3.7°C | 3.7°C | 76 | 12.1 | 9.29 h |
| December | 5.6°C0.7°C | 0.7°C | 95 | 15.1 | 8.38 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Mannheim in SeptemberGermany · 19 kmHigh 20.4°C · Low 11.8°C · 55 mm rain
- Ludwigshafen am Rhein in SeptemberGermany · 19 kmHigh 20.5°C · Low 11.8°C · 55 mm rain
- Worms in SeptemberGermany · 35 kmHigh 20.2°C · Low 11.5°C · 51 mm rain
- Heilbronn in SeptemberGermany · 49 kmHigh 20.0°C · Low 11.6°C · 63 mm rain
- Karlsruhe in SeptemberGermany · 49 kmHigh 20.5°C · Low 12.0°C · 62 mm rain
- Darmstadt in SeptemberGermany · 52 kmHigh 19.8°C · Low 11.4°C · 61 mm rain
- Pforzheim in SeptemberGermany · 58 kmHigh 19.7°C · Low 11.4°C · 64 mm rain
- Kaiserslautern in SeptemberGermany · 67 kmHigh 19.4°C · Low 11.7°C · 60 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Heidelberg) is explained once on the Heidelberg, Germany year overview and on the Sources, method and limits page.