The temperatures in Janesville in September are comfortable with low of 13°C and and high up to 23°C.
You can expect about 3 to 8 days of rain in Janesville 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 Janesville in September 2025.
If you’re planning to visit Janesville in the near future, we highly recommend that you review the 14 day weather forecast for Janesville before you arrive.
Temperatures
23° / 13°
Rainy Days
6
Snowy Days
0
Dry Days
24
Rainfall
90
mm
Sun Hours
7.3
Hrs
