| 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 |
| 1990 Hardiness Zone: | Zone 9b: 25F to 30F |
| Average First Frost Date: | Jan. 11 - Jan. 20 |
| Average Last Frost Date: | Jan. 21 - Jan. 31 |
| 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 95403 - Santa Rosa, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 39 | 41 | 43 | 45 | 48 | 52 | 53 | 53 | 52 | 48 | 42 | 38 | 46 |
| Avg Max Temp (°F) | 58 | 62 | 65 | 70 | 76 | 82 | 85 | 84 | 83 | 77 | 65 | 58 | 72 |
| Avg Precip (In.) | 7.04 | 6.59 | 5.2 | 1.86 | .87 | .21 | .07 | .12 | .5 | 1.85 | 4.78 | 5.11 | 34.19 |