Ellsworth, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.6 °C (low) to 12.4 °C (high). Annual precipitation averages 1226.6 Millimeters. Ellsworth is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.2 °C | -1.4 °C | 99.31 mm |
| February | -11.2 °C | 0.1 °C | 83.82 mm |
| March | -5.8 °C | 4.3 °C | 104.9 mm |
| April | -0.1 °C | 10.9 °C | 109.98 mm |
| May | 5.6 °C | 17 °C | 96.01 mm |
| June | 10.7 °C | 22 °C | 103.89 mm |
| July | 14.2 °C | 25.3 °C | 84.07 mm |
| August | 13.4 °C | 25.1 °C | 79.25 mm |
| September | 9.4 °C | 21.1 °C | 93.73 mm |
| October | 3.6 °C | 14.3 °C | 130.56 mm |
| November | -1.3 °C | 7.8 °C | 122.68 mm |
| December | -7.6 °C | 1.9 °C | 118.36 mm |
| Annual | 1.6 °C | 12.4 °C | 1226.56 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 |