| 2023 Hardiness Zone: | Zone 10a: 30°F to 35°F |
| 2012 Hardiness Zone: | Zone 10a: 30°F to 35°F |
| 1990 Hardiness Zone: | Zone 10a: 30F to 35F |
| 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: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 94403 - San Mateo, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 41 | 43 | 45 | 46 | 50 | 53 | 54 | 55 | 54 | 50 | 45 | 40 | 48 |
| Avg Max Temp (°F) | 58 | 62 | 64 | 68 | 71 | 75 | 77 | 78 | 77 | 74 | 64 | 58 | 69 |
| Avg Precip (In.) | 4.33 | 4.01 | 3.36 | 1.2 | .48 | .14 | .04 | .09 | .24 | 1.14 | 2.74 | 3.02 | 20.78 |