Brownville Junction, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.3 °F (low) to 53.5 °F (high). Annual precipitation averages 45.9 Inches. 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 | 4.0 °F | 25.1 °F | 3.31 in. |
| February | 4.9 °F | 28.7 °F | 2.73 in. |
| March | 16.5 °F | 38.2 °F | 3.27 in. |
| April | 29.0 °F | 51.6 °F | 3.84 in. |
| May | 40.3 °F | 65.0 °F | 3.79 in. |
| June | 50.4 °F | 73.5 °F | 4.57 in. |
| July | 56.2 °F | 78.9 °F | 3.83 in. |
| August | 53.9 °F | 78.2 °F | 3.83 in. |
| September | 46.0 °F | 70.3 °F | 3.71 in. |
| October | 35.2 °F | 56.7 °F | 5.0 in. |
| November | 25.8 °F | 43.4 °F | 4.04 in. |
| December | 13.8 °F | 31.9 °F | 3.98 in. |
| Annual | 31.3 °F | 53.5 °F | 45.9 in. |
| 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 : -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 |