Northport, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37.5 °F (low) to 54.4 °F (high). Annual precipitation averages 48.9 Inches. Northport is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 13.2 °F | 30.7 °F | 4.0 in. |
| February | 14.6 °F | 32.7 °F | 3.26 in. |
| March | 23.4 °F | 40.0 °F | 3.9 in. |
| April | 34.1 °F | 51.1 °F | 4.43 in. |
| May | 44.2 °F | 62.7 °F | 3.83 in. |
| June | 53.3 °F | 71.3 °F | 4.34 in. |
| July | 59.9 °F | 77.4 °F | 3.14 in. |
| August | 59.3 °F | 76.9 °F | 3.24 in. |
| September | 52.5 °F | 69.4 °F | 3.97 in. |
| October | 42.0 °F | 57.3 °F | 5.5 in. |
| November | 32.1 °F | 46.9 °F | 4.69 in. |
| December | 21.1 °F | 36.6 °F | 4.62 in. |
| Annual | 37.5 °F | 54.4 °F | 48.92 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |