The temperatures in Aarau in September are quite cold with temperatures between 8°C and 20°C, warm clothes are a must.
You can expect about 3 to 8 days of rain in Aarau during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Aarau in September 2025.
If you’re planning to visit Aarau in the near future, we highly recommend that you review the 14 day weather forecast for Aarau before you arrive.
Temperatures
20° / 8°
Rainy Days
5
Snowy Days
0
Dry Days
25
Rainfall
109
mm
Sun Hours
10.8
Hrs
