Harrison, Maine has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from 34.7 °F (low) to 55 °F (high). Annual precipitation averages 50.1 Inches. Harrison is located in USDA Plant Hardiness Zone 5b. 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 | 9.2 °F | 28.7 °F | 3.46 in. |
| February | 10.4 °F | 31.9 °F | 3.5 in. |
| March | 20.3 °F | 40.5 °F | 3.91 in. |
| April | 31.8 °F | 53.7 °F | 4.2 in. |
| May | 43.1 °F | 66.4 °F | 3.59 in. |
| June | 53.1 °F | 73.9 °F | 4.79 in. |
| July | 58.7 °F | 79.3 °F | 4.23 in. |
| August | 57.0 °F | 78.1 °F | 4.1 in. |
| September | 49.1 °F | 70.4 °F | 3.94 in. |
| October | 37.8 °F | 57.5 °F | 5.48 in. |
| November | 27.9 °F | 45.3 °F | 4.4 in. |
| December | 17.4 °F | 34.5 °F | 4.48 in. |
| Annual | 34.7 °F | 55 °F | 50.08 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 5b : -15°F to -10°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 |