Glen Ellen, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 7.4 °C (low) to 22.2 °C (high). Annual precipitation averages 987 Millimeters. 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 | 3.9 °C | 14.3 °C | 189.23 mm |
| February | 4.4 °C | 16.2 °C | 207.77 mm |
| March | 5.6 °C | 18.1 °C | 147.57 mm |
| April | 6.2 °C | 20.7 °C | 56.13 mm |
| May | 8.4 °C | 24 °C | 36.58 mm |
| June | 10.2 °C | 27.6 °C | 7.11 mm |
| July | 11.3 °C | 29.3 °C | 0.25 mm |
| August | 11.4 °C | 29.4 °C | 1.78 mm |
| September | 10.3 °C | 28.9 °C | 3.81 mm |
| October | 8.4 °C | 25 °C | 44.2 mm |
| November | 5.4 °C | 18.6 °C | 99.57 mm |
| December | 3.8 °C | 14.2 °C | 193.04 mm |
| Annual | 7.4 °C | 22.2 °C | 987.04 mm |
| 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 : -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 |