The temperatures in Trondheim in September are quite cold with temperatures between 7°C and 14°C, warm clothes are a must.
You can expect rain for roughly half of the month of September in Trondheim. We’re expecting roughly 8 to 15 days of rain, so your rubber boots and umbrella are going to see plenty of use this month if you’re keen on staying dry.
Our weather forecast can give you a great sense of what weather to expect in Trondheim in September 2025.
If you’re planning to visit Trondheim in the near future, we highly recommend that you review the 14 day weather forecast for Trondheim before you arrive.
Temperatures
14° / 7°
Rainy Days
8
Snowy Days
0
Dry Days
22
Rainfall
121
mm
Sun Hours
8.0
Hrs
