| 2023 Hardiness Zone: | 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: | Jan. 21 - Jan. 31 |
| Average Last Frost Date: | Jan. 21 - Jan. 31 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 94544 - Hayward, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 40 | 43 | 44 | 46 | 50 | 54 | 56 | 56 | 55 | 51 | 44 | 39 | 48 |
| Avg Max Temp (°F) | 56 | 60 | 63 | 67 | 71 | 75 | 78 | 79 | 78 | 73 | 63 | 57 | 68 |
| Avg Precip (In.) | 3.82 | 3.64 | 3.05 | 1.23 | .59 | .13 | .04 | .08 | .24 | 1.13 | 2.43 | 2.73 | 19.11 |