| 2023 Hardiness Zone: | Zone 9a: 20°F to 25°F Zone 9b: 25°F to 30°F Zone 10a: 30°F to 35°F |
| 2012 Hardiness Zone: | Zone 9a: 20°F to 25°F Zone 9b: 25°F to 30°F |
| 1990 Hardiness Zone: | Zone 9b: 25F to 30F |
| Average First Frost Date: | Dec. 11 - Dec. 20 |
| Average Last Frost Date: | Mar. 11 - Mar. 20 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 95446 - Guerneville, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 39 | 41 | 42 | 43 | 46 | 49 | 51 | 51 | 50 | 47 | 42 | 39 | 45 |
| Avg Max Temp (°F) | 57 | 60 | 63 | 68 | 74 | 79 | 83 | 82 | 80 | 74 | 63 | 57 | 70 |
| Avg Precip (In.) | 8.28 | 7.51 | 6.09 | 2.21 | .95 | .23 | .07 | .13 | .54 | 2.11 | 5.75 | 6.07 | 39.95 |