| 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 10a: 30F to 35F |
| Average First Frost Date: | Jan. 21 - Jan. 31 |
| Average Last Frost Date: | Jan. 21 - Jan. 31 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 94963 - San Geronimo, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 41 | 43 | 44 | 45 | 48 | 51 | 52 | 52 | 52 | 49 | 45 | 41 | 47 |
| Avg Max Temp (°F) | 55 | 60 | 63 | 68 | 72 | 78 | 81 | 81 | 79 | 74 | 62 | 55 | 69 |
| Avg Precip (In.) | 8.41 | 8.19 | 6.53 | 2.58 | 1.13 | .38 | .09 | .14 | .56 | 2.36 | 6.51 | 6.54 | 43.41 |