| 2023 Hardiness Zone: | Zone 9b: 25°F to 30°F Zone 10a: 30°F to 35°F | |
| 2012 Hardiness Zone: | Zone 9b: 25°F to 30°F Zone 10a: 30°F to 35°F | |
| 1990 Hardiness Zone: | Zone 9b: 25F to 30F | |
| Average First Frost Date: | No Frost | |
| Average Last Frost Date: | No Frost | |
| Koppen-Geiger Climate Zone: | Csa - Hot-Summer Mediterranean Climate | |
| Ecoregion: | ||
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 91 - 120 days Over 86°F |
Annual Climate Data for ZIP Code 91737 - Rancho Cucamonga, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 37 | 38 | 39 | 41 | 46 | 51 | 55 | 57 | 54 | 48 | 42 | 37 | 45 |
| Avg Max Temp (°F) | 59 | 61 | 63 | 69 | 74 | 82 | 89 | 88 | 84 | 75 | 66 | 59 | 72 |
| Avg Precip (In.) | 6.49 | 6.73 | 6.44 | 1.57 | .73 | .12 | .04 | .21 | .51 | 1.02 | 2.13 | 3.64 | 29.63 |