Climate averages 1991–2020
Arnsberg weather
in September.
A mild, moderately wet month: the 4th warmest and the joint 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Arnsberg: daytime highs average 17.3°C and nights cool to about 10.3°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 70 mm of rain on roughly 12 days, which makes September a moderately wet month (the joint 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 42 min on an average September day.
The nearest other city in this atlas is Iserlohn (26 km away). In September its highs average 17.5°C, about as warm as Arnsberg, with 72 mm of rain.
Among the 120 cities listed in Germany, Arnsberg ranks 116th of 120 for the warmest September highs and joint 91st of 120 for the driest September (rainfall, lowest first). The mean September high of those 120 cities is 18.8°C; Arnsberg is 1.5°C cooler than that mean.
From September to October, average highs fall by 4.7°C to 12.6°C, and monthly rainfall stays at 70 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
Arnsberg climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 3.4°C-1.1°C | -1.1°C | 79 | 14.3 | 8.48 h |
| February | 4.3°C-1.3°C | -1.3°C | 65 | 12.5 | 9.910 h |
| March | 8.1°C1.0°C | 1.0°C | 70 | 13.7 | 11.812 h |
| April | 12.6°C4.0°C | 4.0°C | 56 | 11.3 | 13.814 h |
| May | 16.3°C8.0°C | 8.0°C | 68 | 12.8 | 15.616 h |
| June | 19.2°C11.1°C | 11.1°C | 74 | 13.0 | 16.517 h |
| July | 21.3°C13.3°C | 13.3°C | 85 | 14.2 | 16.116 h |
| August | 21.1°C13.3°C | 13.3°C | 84 | 13.3 | 14.615 h |
| September, selected | 17.3°C10.3°C | 10.3°C | 70 | 12.3 | 12.713 h |
| October | 12.6°C7.0°C | 7.0°C | 70 | 12.6 | 10.711 h |
| November | 7.6°C3.2°C | 3.2°C | 72 | 13.5 | 8.99 h |
| December | 4.2°C0.2°C | 0.2°C | 81 | 14.7 | 8.08 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
- Iserlohn in SeptemberGermany · 26 kmHigh 17.5°C · Low 10.6°C · 72 mm rain
- Lüdenscheid in SeptemberGermany · 37 kmHigh 16.7°C · Low 9.9°C · 87 mm rain
- Hamm in SeptemberGermany · 38 kmHigh 18.7°C · Low 11.3°C · 63 mm rain
- Hagen in SeptemberGermany · 43 kmHigh 18.4°C · Low 11.6°C · 92 mm rain
- Dortmund in SeptemberGermany · 45 kmHigh 18.6°C · Low 11.3°C · 75 mm rain
- Lünen in SeptemberGermany · 46 kmHigh 18.9°C · Low 11.5°C · 75 mm rain
- Witten in SeptemberGermany · 51 kmHigh 18.5°C · Low 11.5°C · 74 mm rain
- Siegen in SeptemberGermany · 57 kmHigh 17.6°C · Low 10.4°C · 76 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 Arnsberg) is explained once on the Arnsberg year overview and on the Sources, method and limits page.