Keyport, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 44.2 °F (low) to 60.7 °F (high). Annual precipitation averages 38.7 Inches. Keyport 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 | 36.3 °F | 47.4 °F | 5.94 in. |
| February | 36.2 °F | 49.8 °F | 3.31 in. |
| March | 38.3 °F | 53.7 °F | 4.11 in. |
| April | 41.5 °F | 59.2 °F | 2.75 in. |
| May | 46.6 °F | 65.6 °F | 1.88 in. |
| June | 51.0 °F | 69.7 °F | 1.72 in. |
| July | 54.3 °F | 76.1 °F | 0.85 in. |
| August | 54.4 °F | 77.0 °F | 0.99 in. |
| September | 51.0 °F | 71.4 °F | 1.76 in. |
| October | 45.2 °F | 60.7 °F | 3.58 in. |
| November | 39.5 °F | 51.7 °F | 5.79 in. |
| December | 36.1 °F | 46.5 °F | 6.06 in. |
| Annual | 44.2 °F | 60.7 °F | 38.74 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |