Brownville, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.4 °F (low) to 52.3 °F (high). Annual precipitation averages 45.8 Inches. Brownville is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 5.4 °F | 24.5 °F | 3.29 in. |
| February | 6.6 °F | 27.8 °F | 2.71 in. |
| March | 17.3 °F | 37.2 °F | 3.23 in. |
| April | 29.8 °F | 50.2 °F | 3.82 in. |
| May | 41.3 °F | 63.8 °F | 3.77 in. |
| June | 51.2 °F | 72.1 °F | 4.6 in. |
| July | 56.8 °F | 77.5 °F | 3.88 in. |
| August | 55.0 °F | 76.6 °F | 3.81 in. |
| September | 47.2 °F | 68.9 °F | 3.72 in. |
| October | 36.7 °F | 55.3 °F | 4.99 in. |
| November | 26.7 °F | 42.5 °F | 4.03 in. |
| December | 14.8 °F | 30.9 °F | 3.97 in. |
| Annual | 32.4 °F | 52.3 °F | 45.82 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| 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 |