Waterboro, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.1 °F (low) to 55.7 °F (high). Annual precipitation averages 50.2 Inches. Waterboro is located in USDA Plant Hardiness Zone 5b. 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 | 11.1 °F | 29.3 °F | 3.5 in. |
| February | 11.4 °F | 32.4 °F | 3.56 in. |
| March | 20.6 °F | 40.7 °F | 4.3 in. |
| April | 32.4 °F | 54.3 °F | 4.61 in. |
| May | 43.3 °F | 66.8 °F | 3.71 in. |
| June | 53.1 °F | 75.5 °F | 4.53 in. |
| July | 58.4 °F | 80.7 °F | 4.11 in. |
| August | 56.9 °F | 79.3 °F | 3.76 in. |
| September | 49.2 °F | 71.2 °F | 3.86 in. |
| October | 38.4 °F | 57.3 °F | 5.44 in. |
| November | 28.6 °F | 45.5 °F | 4.28 in. |
| December | 18.0 °F | 34.9 °F | 4.57 in. |
| Annual | 35.1 °F | 55.7 °F | 50.23 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 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 |