Glen Ellen, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 45.4 °F (low) to 72 °F (high). Annual precipitation averages 38.9 Inches. Glen Ellen is located in USDA Plant Hardiness Zone 9b. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 39.0 °F | 57.7 °F | 7.45 in. |
| February | 39.9 °F | 61.2 °F | 8.18 in. |
| March | 42.0 °F | 64.6 °F | 5.81 in. |
| April | 43.2 °F | 69.3 °F | 2.21 in. |
| May | 47.2 °F | 75.2 °F | 1.44 in. |
| June | 50.4 °F | 81.7 °F | 0.28 in. |
| July | 52.3 °F | 84.8 °F | 0.01 in. |
| August | 52.5 °F | 85.0 °F | 0.07 in. |
| September | 50.6 °F | 84.1 °F | 0.15 in. |
| October | 47.2 °F | 77.0 °F | 1.74 in. |
| November | 41.8 °F | 65.5 °F | 3.92 in. |
| December | 38.8 °F | 57.5 °F | 7.6 in. |
| Annual | 45.4 °F | 72 °F | 38.86 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| 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 |