Kittery, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.9 °C (low) to 14.2 °C (high). Annual precipitation averages 1218.2 Millimeters. Kittery is located in USDA Plant Hardiness Zone 6a. 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 | -8.2 °C | 0.8 °C | 92.96 mm |
| February | -7.5 °C | 2.2 °C | 90.68 mm |
| March | -3.7 °C | 6.3 °C | 107.44 mm |
| April | 1.7 °C | 13 °C | 114.3 mm |
| May | 7.2 °C | 18.6 °C | 96.77 mm |
| June | 12.6 °C | 23.9 °C | 107.7 mm |
| July | 15.9 °C | 27.1 °C | 90.17 mm |
| August | 15.3 °C | 26.6 °C | 83.31 mm |
| September | 11.4 °C | 22.4 °C | 96.01 mm |
| October | 5.6 °C | 15.6 °C | 127.51 mm |
| November | 0.4 °C | 9.6 °C | 99.57 mm |
| December | -4.4 °C | 3.8 °C | 111.76 mm |
| Annual | 3.9 °C | 14.2 °C | 1218.18 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |