Greenbush, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.6 °F (low) to 54.2 °F (high). Annual precipitation averages 44.5 Inches. Greenbush is located in USDA Plant Hardiness Zone 5a. 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 | 5.9 °F | 27.2 °F | 3.42 in. |
| February | 7.4 °F | 30.3 °F | 2.77 in. |
| March | 18.8 °F | 39.0 °F | 3.43 in. |
| April | 30.8 °F | 51.8 °F | 3.65 in. |
| May | 41.3 °F | 64.5 °F | 3.49 in. |
| June | 50.4 °F | 73.9 °F | 4.12 in. |
| July | 56.7 °F | 79.4 °F | 3.39 in. |
| August | 54.5 °F | 78.4 °F | 3.4 in. |
| September | 46.7 °F | 70.3 °F | 3.65 in. |
| October | 35.9 °F | 56.9 °F | 4.7 in. |
| November | 27.2 °F | 44.8 °F | 4.07 in. |
| December | 15.4 °F | 33.6 °F | 4.37 in. |
| Annual | 32.6 °F | 54.2 °F | 44.46 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 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |