Climate averages 1991–2020
Bern weather
in September.
A mild, moderately wet month: the 4th warmest and the 5th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a mild month in Bern: daytime highs average 17.7°C and nights cool to about 9.6°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 88 mm of rain on roughly 12 days, which makes September a moderately wet month (the 5th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 37 min on an average September day.
The nearest other city in this atlas is Luzern (66 km away). In September its highs average 18.9°C, 1.2°C warmer than Bern, with 166 mm of rain.
Among the 8 cities listed in Switzerland, Bern ranks 7th of 8 for the warmest September highs and 1st of 8 for the driest September (rainfall, lowest first). The mean September high of those 8 cities is 18.8°C; Bern is 1.1°C cooler than that mean.
From September to October, average highs fall by 3.8°C to 13.9°C, and monthly rainfall falls from 88 mm to 84 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
Bern climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 3.8°C-3.3°C | -3.3°C | 80 | 12.8 | 9.09 h |
| February | 4.9°C-3.3°C | -3.3°C | 73 | 11.7 | 10.310 h |
| March | 8.8°C-0.2°C | -0.2°C | 84 | 13.3 | 11.912 h |
| April | 12.5°C2.7°C | 2.7°C | 90 | 13.6 | 13.614 h |
| May | 16.3°C7.0°C | 7.0°C | 117 | 15.4 | 15.015 h |
| June | 19.8°C10.8°C | 10.8°C | 106 | 14.7 | 15.816 h |
| July | 21.8°C12.9°C | 12.9°C | 104 | 13.5 | 15.515 h |
| August | 21.8°C13.1°C | 13.1°C | 101 | 13.3 | 14.214 h |
| September, selected | 17.7°C9.6°C | 9.6°C | 88 | 11.8 | 12.613 h |
| October | 13.9°C5.8°C | 5.8°C | 84 | 11.9 | 10.911 h |
| November | 8.1°C1.0°C | 1.0°C | 90 | 12.6 | 9.49 h |
| December | 4.4°C-2.1°C | -2.1°C | 93 | 13.5 | 8.69 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
- Luzern in SeptemberSwitzerland · 66 kmHigh 18.9°C · Low 11.6°C · 166 mm rain
- Basel in SeptemberSwitzerland · 69 kmHigh 20.1°C · Low 10.8°C · 95 mm rain
- Lausanne in SeptemberSwitzerland · 79 kmHigh 18.8°C · Low 13.2°C · 108 mm rain
- Mulhouse in SeptemberFrance · 90 kmHigh 19.7°C · Low 11.2°C · 74 mm rain
- Zürich in SeptemberSwitzerland · 95 kmHigh 18.9°C · Low 11.2°C · 123 mm rain
- Besançon in SeptemberFrance · 113 kmHigh 20.2°C · Low 12.0°C · 93 mm rain
- Winterthur in SeptemberSwitzerland · 115 kmHigh 18.7°C · Low 10.8°C · 91 mm rain
- Freiburg in SeptemberGermany · 120 kmHigh 20.0°C · Low 11.8°C · 77 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 Bern) is explained once on the Bern year overview and on the Sources, method and limits page.