Swanville, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35 °F (low) to 54.1 °F (high). Annual precipitation averages 48.6 Inches. Swanville 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.7 °F | 27.9 °F | 3.86 in. |
| February | 10.3 °F | 30.9 °F | 3.28 in. |
| March | 20.5 °F | 39.2 °F | 3.96 in. |
| April | 32.7 °F | 52.0 °F | 4.39 in. |
| May | 43.5 °F | 64.0 °F | 3.76 in. |
| June | 52.8 °F | 72.9 °F | 4.24 in. |
| July | 58.8 °F | 78.7 °F | 3.22 in. |
| August | 57.3 °F | 77.8 °F | 3.35 in. |
| September | 49.4 °F | 70.0 °F | 3.92 in. |
| October | 38.7 °F | 57.2 °F | 5.43 in. |
| November | 29.0 °F | 44.9 °F | 4.56 in. |
| December | 17.8 °F | 33.9 °F | 4.63 in. |
| Annual | 35 °F | 54.1 °F | 48.6 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |