Vassalboro, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.4 °F (low) to 55.1 °F (high). Annual precipitation averages 45.1 Inches. Vassalboro is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 9.8 °F | 28.8 °F | 3.28 in. |
| February | 11.5 °F | 31.8 °F | 2.83 in. |
| March | 21.4 °F | 40.2 °F | 3.57 in. |
| April | 32.9 °F | 53.1 °F | 3.91 in. |
| May | 43.6 °F | 65.2 °F | 3.45 in. |
| June | 53.2 °F | 73.9 °F | 4.11 in. |
| July | 59.1 °F | 79.3 °F | 3.35 in. |
| August | 57.6 °F | 78.5 °F | 3.51 in. |
| September | 49.9 °F | 71.0 °F | 3.77 in. |
| October | 39.0 °F | 58.2 °F | 5.08 in. |
| November | 29.1 °F | 45.8 °F | 4.14 in. |
| December | 18.1 °F | 34.8 °F | 4.14 in. |
| Annual | 35.4 °F | 55.1 °F | 45.14 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |