Yountville, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.4 °F (low) to 72.5 °F (high). Annual precipitation averages 30.2 Inches. Yountville is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 38.0 °F | 57.9 °F | 5.54 in. |
| February | 39.9 °F | 61.2 °F | 6.22 in. |
| March | 41.7 °F | 65.2 °F | 3.89 in. |
| April | 43.4 °F | 71.8 °F | 1.93 in. |
| May | 47.7 °F | 74.6 °F | 1.19 in. |
| June | 50.9 °F | 83.5 °F | 0.12 in. |
| July | 53.0 °F | 85.3 °F | 0.0 in. |
| August | 53.2 °F | 84.2 °F | 0.02 in. |
| September | 50.6 °F | 84.8 °F | 0.13 in. |
| October | 46.9 °F | 78.2 °F | 1.25 in. |
| November | 41.3 °F | 65.6 °F | 3.27 in. |
| December | 37.9 °F | 57.7 °F | 6.65 in. |
| Annual | 45.4 °F | 72.5 °F | 30.21 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |