Boothbay, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.4 °C (low) to 11.7 °C (high). Annual precipitation averages 1256.8 Millimeters. Boothbay is located in USDA Plant Hardiness Zone 6a. 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 | -6.8 °C | 0.3 °C | 100.08 mm |
| February | -6.2 °C | 1.2 °C | 93.47 mm |
| March | -2.7 °C | 4.2 °C | 114.55 mm |
| April | 2.1 °C | 9.5 °C | 111 mm |
| May | 7 °C | 14.8 °C | 92.96 mm |
| June | 11.4 °C | 19.6 °C | 109.22 mm |
| July | 14.7 °C | 22.9 °C | 88.39 mm |
| August | 15 °C | 22.8 °C | 79.76 mm |
| September | 12.2 °C | 19.3 °C | 102.87 mm |
| October | 7.3 °C | 13.6 °C | 130.56 mm |
| November | 2.4 °C | 8.5 °C | 112.01 mm |
| December | -3.1 °C | 3.6 °C | 121.92 mm |
| Annual | 4.4 °C | 11.7 °C | 1256.79 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |