Machias, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.5 °C (low) to 12.1 °C (high). Annual precipitation averages 1344.4 Millimeters. Machias is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -13 °C | -1.2 °C | 119.63 mm |
| February | -11.6 °C | -0.1 °C | 96.52 mm |
| March | -6.9 °C | 4.1 °C | 119.89 mm |
| April | -0.8 °C | 10.2 °C | 108.71 mm |
| May | 4.6 °C | 16.1 °C | 104.14 mm |
| June | 9.3 °C | 21.2 °C | 97.79 mm |
| July | 12.2 °C | 24.3 °C | 88.9 mm |
| August | 11.9 °C | 24.8 °C | 82.55 mm |
| September | 7.9 °C | 20.8 °C | 104.65 mm |
| October | 2.2 °C | 14.6 °C | 144.53 mm |
| November | -2 °C | 8.1 °C | 136.65 mm |
| December | -7.7 °C | 2.3 °C | 140.46 mm |
| Annual | 0.5 °C | 12.1 °C | 1344.42 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |