| 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 9a: 20°F to 25°F 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. 1 - Dec. 10 |
| Average Last Frost Date: | Mar. 11 - Mar. 20 |
| 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 94517 - Clayton, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 38 | 41 | 42 | 45 | 49 | 54 | 57 | 58 | 56 | 50 | 43 | 38 | 48 |
| Avg Max Temp (°F) | 56 | 60 | 64 | 69 | 75 | 82 | 88 | 88 | 85 | 77 | 64 | 57 | 72 |
| Avg Precip (In.) | 4.11 | 3.77 | 2.66 | 1.41 | .91 | .11 | .04 | .06 | .2 | 1.12 | 2.01 | 2.83 | 19.23 |