Windsor, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.4 °F (low) to 71.3 °F (high). Annual precipitation averages 38.5 Inches. Windsor is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 11 - Feb. 20 through the first frost around Dec. 11 - Dec. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 37.9 °F | 57.7 °F | 7.85 in. |
| February | 39.3 °F | 61.2 °F | 7.66 in. |
| March | 41.2 °F | 64.5 °F | 5.25 in. |
| April | 42.8 °F | 68.7 °F | 2.42 in. |
| May | 46.2 °F | 74.3 °F | 1.45 in. |
| June | 49.6 °F | 80.6 °F | 0.31 in. |
| July | 51.6 °F | 82.7 °F | 0.02 in. |
| August | 51.5 °F | 83.2 °F | 0.07 in. |
| September | 49.2 °F | 82.7 °F | 0.13 in. |
| October | 45.3 °F | 76.8 °F | 1.74 in. |
| November | 40.4 °F | 65.5 °F | 3.94 in. |
| December | 37.2 °F | 57.7 °F | 7.68 in. |
| Annual | 44.4 °F | 71.3 °F | 38.52 in. |
| Average First Frost Date | Dec. 11 - Dec. 20 |
| Average Last Frost Date | Feb. 11 - Feb. 20 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |