Boonville, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.8 °F (low) to 72 °F (high). Annual precipitation averages 41.3 Inches. Boonville is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Dec. 1 - Dec. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.2 °F | 57.4 °F | 8.37 in. |
| February | 40.1 °F | 59.4 °F | 6.63 in. |
| March | 41.8 °F | 62.7 °F | 5.65 in. |
| April | 43.8 °F | 67.9 °F | 3.21 in. |
| May | 47.6 °F | 74.5 °F | 1.47 in. |
| June | 51.4 °F | 81.4 °F | 0.3 in. |
| July | 53.4 °F | 88.1 °F | 0.03 in. |
| August | 53.2 °F | 88.0 °F | 0.06 in. |
| September | 51.2 °F | 86.1 °F | 0.14 in. |
| October | 47.0 °F | 77.6 °F | 1.74 in. |
| November | 42.0 °F | 63.4 °F | 4.29 in. |
| December | 38.6 °F | 57.1 °F | 9.43 in. |
| Annual | 45.8 °F | 72 °F | 41.32 in. |
| Average First Frost Date | Dec. 1 - Dec. 10 |
| Average Last Frost Date | Mar. 11 - Mar. 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 |