Kirkwood, California has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from -0.6 °C (low) to 11.9 °C (high). Annual precipitation averages 1419.1 Millimeters. Kirkwood is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.2 °C | 4.3 °C | 243.59 mm |
| February | -6.8 °C | 4.3 °C | 223.77 mm |
| March | -5.7 °C | 6.2 °C | 206.25 mm |
| April | -4.1 °C | 8.3 °C | 115.57 mm |
| May | -0.3 °C | 12.5 °C | 86.61 mm |
| June | 4 °C | 18 °C | 28.19 mm |
| July | 8.2 °C | 22.7 °C | 10.41 mm |
| August | 7.9 °C | 22.4 °C | 9.4 mm |
| September | 5.3 °C | 19.4 °C | 19.3 mm |
| October | 0.8 °C | 13.7 °C | 79.5 mm |
| November | -3.6 °C | 7.6 °C | 150.62 mm |
| December | -6.4 °C | 3.7 °C | 245.87 mm |
| Annual | -0.6 °C | 11.9 °C | 1419.08 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |