Littleton, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30.8 °F (low) to 51.6 °F (high). Annual precipitation averages 43.7 Inches. Littleton is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.5 °F | 22.8 °F | 3.38 in. |
| February | 4.1 °F | 26.0 °F | 2.67 in. |
| March | 15.5 °F | 35.7 °F | 3.31 in. |
| April | 29.0 °F | 49.2 °F | 3.14 in. |
| May | 40.3 °F | 63.8 °F | 3.57 in. |
| June | 49.9 °F | 73.2 °F | 4.42 in. |
| July | 55.5 °F | 77.9 °F | 3.99 in. |
| August | 53.5 °F | 76.7 °F | 3.56 in. |
| September | 45.9 °F | 68.6 °F | 3.59 in. |
| October | 35.6 °F | 54.8 °F | 4.21 in. |
| November | 25.6 °F | 40.9 °F | 3.8 in. |
| December | 12.6 °F | 29.4 °F | 4.07 in. |
| Annual | 30.8 °F | 51.6 °F | 43.71 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |