The weather in Rancho Cucamonga in September is hot. The average temperatures are between 21°C and 31°C.
There shouldn't be any rainy days in in Rancho Cucamonga during September. Having said that, the days are very hot in September so hanging out outside is more recomanded during the after noons and evening time.
Our weather forecast can give you a great sense of what weather to expect in Rancho Cucamonga in September 2025.
If you’re planning to visit Rancho Cucamonga in the near future, we highly recommend that you review the 14 day weather forecast for Rancho Cucamonga before you arrive.
Temperatures
31° / 21°
Rainy Days
0
Snowy Days
0
Dry Days
30
Rainfall
5
mm
Sun Hours
11.9
Hrs
