Brownville, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.2 °C (low) to 11.3 °C (high). Annual precipitation averages 1163.8 Millimeters. 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 | -14.8 °C | -4.2 °C | 83.57 mm |
| February | -14.1 °C | -2.3 °C | 68.83 mm |
| March | -8.2 °C | 2.9 °C | 82.04 mm |
| April | -1.2 °C | 10.1 °C | 97.03 mm |
| May | 5.2 °C | 17.7 °C | 95.76 mm |
| June | 10.7 °C | 22.3 °C | 116.84 mm |
| July | 13.8 °C | 25.3 °C | 98.55 mm |
| August | 12.8 °C | 24.8 °C | 96.77 mm |
| September | 8.4 °C | 20.5 °C | 94.49 mm |
| October | 2.6 °C | 12.9 °C | 126.75 mm |
| November | -2.9 °C | 5.8 °C | 102.36 mm |
| December | -9.6 °C | -0.6 °C | 100.84 mm |
| Annual | 0.2 °C | 11.3 °C | 1163.83 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |