Westport, Washington has a Temperate Oceanic Climate climate (Köppen classification: Cfb). Average annual temperatures range from 45.5 °F (low) to 57.3 °F (high). Annual precipitation averages 78.8 Inches. Westport 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 | 39.6 °F | 48.4 °F | 12.01 in. |
| February | 38.8 °F | 50.4 °F | 7.3 in. |
| March | 40.3 °F | 52.6 °F | 9.07 in. |
| April | 42.7 °F | 55.4 °F | 6.13 in. |
| May | 47.0 °F | 59.2 °F | 3.42 in. |
| June | 50.6 °F | 62.3 °F | 2.63 in. |
| July | 53.4 °F | 65.2 °F | 1.18 in. |
| August | 53.5 °F | 66.7 °F | 1.65 in. |
| September | 51.7 °F | 66.1 °F | 2.95 in. |
| October | 46.9 °F | 60.0 °F | 8.13 in. |
| November | 42.2 °F | 52.8 °F | 11.94 in. |
| December | 38.8 °F | 48.0 °F | 12.37 in. |
| Annual | 45.5 °F | 57.3 °F | 78.78 in. |
| 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 : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 9a : 20°F to 25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfb - Temperate Oceanic Climate |