| 2023 Hardiness Zone: | Zone 9a: 20°F to 25°F Zone 9b: 25°F to 30°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: | Feb. 21 - Feb. 29 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 95401 - Santa Rosa, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 38 | 41 | 43 | 44 | 48 | 51 | 52 | 52 | 51 | 47 | 42 | 38 | 46 |
| Avg Max Temp (°F) | 57 | 62 | 65 | 70 | 75 | 81 | 83 | 83 | 82 | 77 | 65 | 58 | 72 |
| Avg Precip (In.) | 6.54 | 6.17 | 4.85 | 1.7 | .85 | .21 | .06 | .11 | .49 | 1.84 | 4.56 | 4.76 | 32.14 |