Farmington, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.2 °F (low) to 54.2 °F (high). Annual precipitation averages 47.9 Inches. Farmington 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.3 °F | 27.4 °F | 3.51 in. |
| February | 8.5 °F | 30.4 °F | 3.0 in. |
| March | 19.1 °F | 39.1 °F | 3.95 in. |
| April | 31.0 °F | 52.2 °F | 4.07 in. |
| May | 42.0 °F | 65.0 °F | 3.9 in. |
| June | 51.7 °F | 73.6 °F | 4.71 in. |
| July | 57.2 °F | 78.7 °F | 3.82 in. |
| August | 55.3 °F | 77.9 °F | 3.78 in. |
| September | 47.2 °F | 70.5 °F | 3.31 in. |
| October | 36.6 °F | 57.3 °F | 5.37 in. |
| November | 26.9 °F | 44.5 °F | 4.21 in. |
| December | 16.0 °F | 33.3 °F | 4.26 in. |
| Annual | 33.2 °F | 54.2 °F | 47.89 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |