The temperatures in Simi Valley in September are comfortable with low of 18°C and and high up to 26°C.
As it is almost never rain during September in Simi Valley the weather is perfect for hanging out outside and exploring all that Simi Valley has to offer.
Our weather forecast can give you a great sense of what weather to expect in Simi Valley in September 2025.
If you’re planning to visit Simi Valley in the near future, we highly recommend that you review the 14 day weather forecast for Simi Valley before you arrive.
Temperatures
26° / 18°
Rainy Days
0
Snowy Days
0
Dry Days
30
Rainfall
9
mm
Sun Hours
11.5
Hrs