| 2023 Hardiness Zone: | Zone 10b: 35°F to 40°F | |
| 2012 Hardiness Zone: | Zone 10a: 30°F to 35°F | |
| 1990 Hardiness Zone: | Zone 10a: 30F to 35F | |
| Average First Frost Date: | Jan. 1 - Jan. 10 | |
| Average Last Frost Date: | Jan. 21 - Jan. 31 | |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate | |
| Ecoregion: | ||
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 1 - 7 days Over 86°F |
Annual Climate Data for ZIP Code 91942 - La Mesa, CA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 43 | 45 | 47 | 50 | 55 | 58 | 62 | 64 | 61 | 55 | 47 | 42 | 52 |
| Avg Max Temp (°F) | 68 | 69 | 71 | 73 | 75 | 80 | 85 | 87 | 85 | 80 | 73 | 68 | 76 |
| Avg Precip (In.) | 2.9 | 2.62 | 2.96 | 1.07 | .33 | .11 | .05 | .1 | .29 | .56 | 1.32 | 1.58 | 13.9 |