Lebanon, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.9 °F (low) to 57 °F (high). Annual precipitation averages 49.7 Inches. Lebanon 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 | 13.9 °F | 31.2 °F | 3.54 in. |
| February | 14.8 °F | 34.1 °F | 3.46 in. |
| March | 23.2 °F | 42.1 °F | 4.41 in. |
| April | 33.7 °F | 55.7 °F | 4.37 in. |
| May | 44.4 °F | 66.9 °F | 3.79 in. |
| June | 54.2 °F | 75.9 °F | 4.44 in. |
| July | 59.5 °F | 81.4 °F | 4.05 in. |
| August | 58.3 °F | 80.0 °F | 3.8 in. |
| September | 50.5 °F | 72.5 °F | 3.89 in. |
| October | 39.7 °F | 59.5 °F | 5.07 in. |
| November | 29.9 °F | 47.5 °F | 4.31 in. |
| December | 20.7 °F | 36.8 °F | 4.59 in. |
| Annual | 36.9 °F | 57 °F | 49.72 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°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 |