Porter, Maine has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from 32.6 °F (low) to 55.3 °F (high). Annual precipitation averages 51.4 Inches. Porter is located in USDA Plant Hardiness Zone 5a. 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 | 7.7 °F | 29.1 °F | 3.59 in. |
| February | 8.8 °F | 32.1 °F | 3.66 in. |
| March | 18.7 °F | 40.7 °F | 4.33 in. |
| April | 30.2 °F | 53.9 °F | 4.41 in. |
| May | 41.2 °F | 66.6 °F | 3.77 in. |
| June | 50.9 °F | 74.6 °F | 4.74 in. |
| July | 56.0 °F | 80.0 °F | 4.46 in. |
| August | 54.1 °F | 78.7 °F | 3.87 in. |
| September | 46.2 °F | 71.0 °F | 3.88 in. |
| October | 35.4 °F | 57.6 °F | 5.51 in. |
| November | 26.4 °F | 45.0 °F | 4.5 in. |
| December | 15.9 °F | 34.4 °F | 4.66 in. |
| Annual | 32.6 °F | 55.3 °F | 51.38 in. |
| 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |