| 2023 Hardiness Zone: | Zone 9b: 25°F to 30°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: | Jan. 1 - Jan. 10 |
| Average Last Frost Date: | Feb. 1 - Feb. 10 |
| 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 94591 - Vallejo, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 39 | 42 | 44 | 46 | 50 | 54 | 55 | 56 | 55 | 51 | 45 | 39 | 48 |
| Avg Max Temp (°F) | 55 | 60 | 64 | 68 | 73 | 78 | 81 | 82 | 80 | 75 | 64 | 56 | 69 |
| Avg Precip (In.) | 5.18 | 4.52 | 3.37 | 1.43 | .69 | .16 | .04 | .07 | .31 | 1.38 | 2.93 | 3.5 | 23.58 |