Yountville, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.4 °C (low) to 22.5 °C (high). Annual precipitation averages 767.4 Millimeters. 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 | 3.3 °C | 14.4 °C | 140.72 mm |
| February | 4.4 °C | 16.2 °C | 157.99 mm |
| March | 5.4 °C | 18.4 °C | 98.81 mm |
| April | 6.3 °C | 22.1 °C | 49.02 mm |
| May | 8.7 °C | 23.7 °C | 30.23 mm |
| June | 10.5 °C | 28.6 °C | 3.05 mm |
| July | 11.7 °C | 29.6 °C | 0 mm |
| August | 11.8 °C | 29 °C | 0.51 mm |
| September | 10.3 °C | 29.3 °C | 3.3 mm |
| October | 8.3 °C | 25.7 °C | 31.75 mm |
| November | 5.2 °C | 18.7 °C | 83.06 mm |
| December | 3.3 °C | 14.3 °C | 168.91 mm |
| Annual | 7.4 °C | 22.5 °C | 767.35 mm |
| 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 : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |