The temperatures in Sonoma in September are comfortable with low of 13°C and and high up to 28°C.
There is little to no rain in Sonoma during September, so it’s a lot easier to explore the city. Just remember to dress in warm layers, as it can still get pretty chilly.
Our weather forecast can give you a great sense of what weather to expect in Sonoma in September 2025.
If you’re planning to visit Sonoma in the near future, we highly recommend that you review the 14 day weather forecast for Sonoma before you arrive.
Temperatures
28° / 13°
Rainy Days
0
Snowy Days
0
Dry Days
30
Rainfall
4
mm
Sun Hours
11.2
Hrs
