Cohassett Beach, Washington has a Temperate Oceanic Climate climate (Köppen classification: Cfb). Average annual temperatures range from 7.4 °C (low) to 13.9 °C (high). Annual precipitation averages 1942.8 Millimeters. Cohassett Beach is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4 °C | 9.2 °C | 298.7 mm |
| February | 3.8 °C | 10.3 °C | 180.59 mm |
| March | 4.6 °C | 11.4 °C | 224.03 mm |
| April | 5.8 °C | 12.8 °C | 152.91 mm |
| May | 8.3 °C | 14.8 °C | 86.87 mm |
| June | 10.1 °C | 16.6 °C | 64.52 mm |
| July | 11.9 °C | 18.1 °C | 29.46 mm |
| August | 11.8 °C | 18.9 °C | 41.4 mm |
| September | 10.8 °C | 18.6 °C | 72.39 mm |
| October | 8.2 °C | 15.4 °C | 198.63 mm |
| November | 5.7 °C | 11.6 °C | 295.91 mm |
| December | 3.8 °C | 8.9 °C | 297.43 mm |
| Annual | 7.4 °C | 13.9 °C | 1942.84 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Cfb - Temperate Oceanic Climate |