| 2023 Hardiness Zone: | 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 10a: 30F to 35F | |
| 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 91773 - San Dimas, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 41 | 43 | 44 | 46 | 50 | 54 | 59 | 59 | 58 | 52 | 45 | 41 | 49 |
| Avg Max Temp (°F) | 65 | 66 | 67 | 73 | 76 | 83 | 89 | 90 | 86 | 79 | 71 | 66 | 76 |
| Avg Precip (In.) | 4.43 | 4.79 | 4.07 | 1.08 | .41 | .09 | .03 | .15 | .45 | .75 | 1.55 | 2.38 | 20.19 |