| 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: | Jan. 1 - Jan. 10 | |
| Average Last Frost Date: | Jan. 21 - Jan. 31 | |
| 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 92337 - Fontana, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 44 | 46 | 46 | 48 | 53 | 57 | 61 | 62 | 60 | 55 | 47 | 43 | 52 |
| Avg Max Temp (°F) | 68 | 69 | 71 | 76 | 80 | 87 | 94 | 94 | 90 | 82 | 74 | 68 | 79 |
| Avg Precip (In.) | 3.4 | 3.34 | 3.2 | .64 | .22 | .03 | .01 | .12 | .27 | .25 | 1.21 | 1.64 | 14.33 |