Carson, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 5.6 °C (low) to 16.5 °C (high). Annual precipitation averages 1608.1 Millimeters. Carson is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.3 °C | 5.8 °C | 224.03 mm |
| February | 0.7 °C | 8.5 °C | 177.04 mm |
| March | 2 °C | 11.9 °C | 176.53 mm |
| April | 4.2 °C | 15.6 °C | 129.79 mm |
| May | 7.2 °C | 20.1 °C | 85.09 mm |
| June | 9.9 °C | 23.1 °C | 45.21 mm |
| July | 12.4 °C | 27.7 °C | 14.99 mm |
| August | 12.3 °C | 28 °C | 12.45 mm |
| September | 9.3 °C | 24.5 °C | 52.32 mm |
| October | 5.9 °C | 17.1 °C | 163.07 mm |
| November | 2.8 °C | 9.9 °C | 244.86 mm |
| December | 0.3 °C | 5.6 °C | 282.7 mm |
| Annual | 5.6 °C | 16.5 °C | 1608.08 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |