| 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 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: | Dec. 21 - Dec. 31 |
| Average Last Frost Date: | Feb. 1 - Feb. 10 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 95409 - Santa Rosa, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 38 | 40 | 42 | 44 | 47 | 51 | 54 | 53 | 52 | 48 | 42 | 38 | 46 |
| Avg Max Temp (°F) | 56 | 60 | 62 | 69 | 75 | 81 | 85 | 85 | 83 | 75 | 63 | 56 | 71 |
| Avg Precip (In.) | 7.69 | 7.55 | 5.62 | 2.02 | .93 | .21 | .07 | .12 | .5 | 1.97 | 5.11 | 5.55 | 37.33 |