Rancho Cucamonga, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 11.4 °C (low) to 25.6 °C (high). Annual precipitation averages 420.9 Millimeters. Rancho Cucamonga is located in USDA Plant Hardiness Zone 10a.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.7 °C | 19.3 °C | 90.42 mm |
| February | 7.1 °C | 19.4 °C | 113.03 mm |
| March | 8.3 °C | 21.2 °C | 68.83 mm |
| April | 9.6 °C | 23.4 °C | 22.35 mm |
| May | 11.9 °C | 25.7 °C | 10.92 mm |
| June | 14.2 °C | 29.3 °C | 2.29 mm |
| July | 16.9 °C | 32.9 °C | 1.27 mm |
| August | 17.4 °C | 33.9 °C | 0.76 mm |
| September | 16.3 °C | 32.2 °C | 4.32 mm |
| October | 13.1 °C | 27.5 °C | 18.8 mm |
| November | 9.1 °C | 23.1 °C | 24.64 mm |
| December | 6.4 °C | 18.7 °C | 63.25 mm |
| Annual | 11.4 °C | 25.6 °C | 420.88 mm |
| Average First Frost Date | No Frost |
| Average Last Frost Date | |
| Average Days With Frost | Frost Free |
| Plant Hardiness Zone | Zone 10a : -1.1°C to 1.7°C |
| Plant Hardiness Zone - 2012 | Zone 10a : -1.1°C to 1.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |