| 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. 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 94401 - San Mateo, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 42 | 44 | 46 | 47 | 50 | 53 | 55 | 55 | 55 | 52 | 47 | 42 | 49 |
| Avg Max Temp (°F) | 58 | 61 | 63 | 67 | 70 | 73 | 75 | 75 | 76 | 73 | 64 | 58 | 68 |
| Avg Precip (In.) | 4.73 | 4.2 | 3.44 | 1.27 | .53 | .14 | .05 | .06 | .25 | 1.24 | 3.03 | 3.14 | 22.09 |