Gouldsboro, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3 °C (low) to 12.1 °C (high). Annual precipitation averages 1332.2 Millimeters. Gouldsboro is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.5 °C | -0.6 °C | 115.06 mm |
| February | -8.6 °C | 0.3 °C | 96.52 mm |
| March | -4.4 °C | 4.1 °C | 118.36 mm |
| April | 1.2 °C | 10.2 °C | 111.76 mm |
| May | 6.3 °C | 16.1 °C | 109.22 mm |
| June | 11.1 °C | 21.2 °C | 103.38 mm |
| July | 14.3 °C | 24.3 °C | 81.79 mm |
| August | 14.3 °C | 24.2 °C | 74.17 mm |
| September | 10.9 °C | 20.1 °C | 102.87 mm |
| October | 5.7 °C | 13.9 °C | 142.75 mm |
| November | 0.4 °C | 8.1 °C | 136.65 mm |
| December | -5.6 °C | 2.9 °C | 139.7 mm |
| Annual | 3 °C | 12.1 °C | 1332.23 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |