More often than not the weather in Rancho Cucamonga during the month of September is 21 with a general average high of 29 with low of 16. See our table below for a full breakdown:
| Month | Degrees Celsius |
|---|---|
| Temperature | 21 |
| High Temperature | 29 |
| Low Temperature | 16 |
| Sunshine Per Day | 10 |
Useful Links: Rancho Cucamonga Weather: Average Weather & Yearly Climate