Vallecito, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 46.2 °F (low) to 73.7 °F (high). Annual precipitation averages 34.5 Inches. Vallecito is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 35.9 °F | 55.9 °F | 6.82 in. |
| February | 36.8 °F | 58.5 °F | 5.76 in. |
| March | 39.5 °F | 63.4 °F | 5.18 in. |
| April | 42.0 °F | 67.8 °F | 3.06 in. |
| May | 47.5 °F | 76.9 °F | 1.75 in. |
| June | 53.8 °F | 87.1 °F | 0.48 in. |
| July | 60.5 °F | 95.1 °F | 0.08 in. |
| August | 59.7 °F | 94.4 °F | 0.2 in. |
| September | 55.6 °F | 88.9 °F | 0.23 in. |
| October | 48.1 °F | 77.6 °F | 1.69 in. |
| November | 39.9 °F | 64.3 °F | 3.25 in. |
| December | 35.6 °F | 55.0 °F | 5.96 in. |
| Annual | 46.2 °F | 73.7 °F | 34.46 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |