Port Townsend, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6.5 °C (low) to 14.5 °C (high). Annual precipitation averages 532.9 Millimeters. Port Townsend 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 | 2.8 °C | 7.9 °C | 61.72 mm |
| February | 2.6 °C | 9 °C | 46.48 mm |
| March | 3.7 °C | 11.1 °C | 54.1 mm |
| April | 5.3 °C | 13.8 °C | 43.94 mm |
| May | 7.8 °C | 16.8 °C | 40.13 mm |
| June | 9.8 °C | 19.1 °C | 34.29 mm |
| July | 11.2 °C | 21.8 °C | 18.54 mm |
| August | 11.2 °C | 22.2 °C | 16 mm |
| September | 9.6 °C | 19.6 °C | 26.42 mm |
| October | 6.9 °C | 14.6 °C | 45.47 mm |
| November | 4.5 °C | 10.3 °C | 76.96 mm |
| December | 2.7 °C | 7.7 °C | 68.83 mm |
| Annual | 6.5 °C | 14.5 °C | 532.88 mm |
| 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 : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 9a : -6.7°C to -3.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |