| 2023 Hardiness Zone: | Zone 9b: 25°F to 30°F |
| 2012 Hardiness Zone: | 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. 11 - Feb. 20 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | 91 - 120 days Over 86°F |
Annual Climate Data for ZIP Code 94571 - Rio Vista, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 37 | 41 | 44 | 47 | 51 | 56 | 58 | 57 | 55 | 50 | 43 | 37 | 48 |
| Avg Max Temp (°F) | 54 | 61 | 66 | 72 | 79 | 86 | 90 | 90 | 86 | 78 | 64 | 54 | 73 |
| Avg Precip (In.) | 3.75 | 3.28 | 2.7 | 1.06 | .59 | .13 | .04 | .05 | .27 | .95 | 2.1 | 2.63 | 17.55 |