Machias, Washington has a Warm-Summer Mediterranean Climate climate (Köppen classification: Csb). Average annual temperatures range from 6 °C (low) to 15.4 °C (high). Annual precipitation averages 1209.5 Millimeters. Machias is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.3 °C | 7.9 °C | 157.23 mm |
| February | 1.3 °C | 9.7 °C | 109.73 mm |
| March | 2.7 °C | 11.9 °C | 127.25 mm |
| April | 4.8 °C | 14.5 °C | 103.12 mm |
| May | 7.7 °C | 18.2 °C | 73.91 mm |
| June | 10.1 °C | 20.3 °C | 69.85 mm |
| July | 11.8 °C | 23.6 °C | 28.7 mm |
| August | 11.8 °C | 24.1 °C | 27.94 mm |
| September | 9.5 °C | 21.2 °C | 63.75 mm |
| October | 6.1 °C | 15.3 °C | 119.89 mm |
| November | 3.2 °C | 10.5 °C | 172.97 mm |
| December | 1.2 °C | 7.4 °C | 155.19 mm |
| Annual | 6 °C | 15.4 °C | 1209.53 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Csb - Warm-Summer Mediterranean Climate |