Brownville Junction, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.4 °C (low) to 11.9 °C (high). Annual precipitation averages 1165.9 Millimeters. Brownville Junction 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 | -15.6 °C | -3.8 °C | 84.07 mm |
| February | -15.1 °C | -1.8 °C | 69.34 mm |
| March | -8.6 °C | 3.4 °C | 83.06 mm |
| April | -1.7 °C | 10.9 °C | 97.54 mm |
| May | 4.6 °C | 18.3 °C | 96.27 mm |
| June | 10.2 °C | 23.1 °C | 116.08 mm |
| July | 13.4 °C | 26.1 °C | 97.28 mm |
| August | 12.2 °C | 25.7 °C | 97.28 mm |
| September | 7.8 °C | 21.3 °C | 94.23 mm |
| October | 1.8 °C | 13.7 °C | 127 mm |
| November | -3.4 °C | 6.3 °C | 102.62 mm |
| December | -10.1 °C | -0.1 °C | 101.09 mm |
| Annual | -0.4 °C | 11.9 °C | 1165.86 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| 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 |