Washburn, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.2 °C (low) to 10.1 °C (high). Annual precipitation averages 1032 Millimeters. Washburn is located in USDA Plant Hardiness Zone 4a. 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 | -17.7 °C | -6.1 °C | 81.53 mm |
| February | -16.9 °C | -4.4 °C | 61.21 mm |
| March | -10.3 °C | 1.1 °C | 69.6 mm |
| April | -2.1 °C | 8.6 °C | 77.22 mm |
| May | 4.6 °C | 16.9 °C | 84.58 mm |
| June | 9.8 °C | 22.2 °C | 101.09 mm |
| July | 13.1 °C | 24.8 °C | 99.31 mm |
| August | 11.9 °C | 24.3 °C | 90.93 mm |
| September | 7.6 °C | 19.8 °C | 86.61 mm |
| October | 1.6 °C | 11.9 °C | 104.65 mm |
| November | -3.9 °C | 4.4 °C | 84.84 mm |
| December | -11.6 °C | -2.3 °C | 90.42 mm |
| Annual | -1.2 °C | 10.1 °C | 1031.99 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 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |