Palmyra, Maine has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.1 °F (low) to 54.6 °F (high). Annual precipitation averages 45.4 Inches. Palmyra 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 | 6.2 °F | 27.0 °F | 3.49 in. |
| February | 7.6 °F | 30.6 °F | 2.87 in. |
| March | 18.6 °F | 39.6 °F | 3.62 in. |
| April | 30.8 °F | 52.9 °F | 3.91 in. |
| May | 42.0 °F | 65.9 °F | 3.47 in. |
| June | 51.7 °F | 74.3 °F | 4.2 in. |
| July | 57.4 °F | 79.7 °F | 3.37 in. |
| August | 55.5 °F | 78.6 °F | 3.51 in. |
| September | 47.6 °F | 71.1 °F | 3.76 in. |
| October | 36.7 °F | 57.8 °F | 4.75 in. |
| November | 27.1 °F | 44.8 °F | 4.23 in. |
| December | 15.4 °F | 33.3 °F | 4.24 in. |
| Annual | 33.1 °F | 54.6 °F | 45.42 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 4b : -25°F to -20°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |