Geneva Weather in September

The climate in Geneva during September can be summarized as hot, humid and wet.

September is in the fall / autumn in Geneva and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a steamy 31°C (88°F), whilst at night 22°C (72°F) is normal.

On average September is the 2nd wettest month of the year in Geneva with around 175mm 6.9 inches of rain making it a wet time to visit. This rainfall is typically spread over 14 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.3 hours of sunshine per day.

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Geneva in September 2025.