Cottonwood, California has a Hot-Summer Mediterranean Climate climate (Köppen classification: Csa). Average annual temperatures range from 9 °C (low) to 24.4 °C (high). Annual precipitation averages 799.9 Millimeters. Cottonwood is located in USDA Plant Hardiness Zone 9a. 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 | 2.6 °C | 13.7 °C | 154.18 mm |
| February | 3.8 °C | 15.9 °C | 120.9 mm |
| March | 5.3 °C | 18.6 °C | 111.76 mm |
| April | 7.2 °C | 21.9 °C | 56.13 mm |
| May | 11 °C | 27.2 °C | 41.66 mm |
| June | 15 °C | 32.5 °C | 24.64 mm |
| July | 17.2 °C | 36.6 °C | 1.52 mm |
| August | 15.9 °C | 35.6 °C | 3.56 mm |
| September | 13.3 °C | 32.9 °C | 10.92 mm |
| October | 9.2 °C | 26.1 °C | 40.64 mm |
| November | 4.7 °C | 18.1 °C | 83.06 mm |
| December | 2.5 °C | 13.2 °C | 150.88 mm |
| Annual | 9 °C | 24.4 °C | 799.85 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csa - Hot-Summer Mediterranean Climate |