Palmyra, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 16.9 °C (high). Annual precipitation averages 1167.4 Millimeters. Palmyra is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.8 °C | 3.2 °C | 80.77 mm |
| February | -5.2 °C | 4.7 °C | 64.01 mm |
| March | -0.9 °C | 9.7 °C | 95.76 mm |
| April | 4.8 °C | 16.8 °C | 93.22 mm |
| May | 10.4 °C | 22.4 °C | 100.08 mm |
| June | 15.7 °C | 27.2 °C | 111.25 mm |
| July | 18.1 °C | 29.8 °C | 116.33 mm |
| August | 17.1 °C | 28.7 °C | 103.38 mm |
| September | 13.1 °C | 24.9 °C | 122.43 mm |
| October | 6.7 °C | 18.2 °C | 107.19 mm |
| November | 1.2 °C | 11.8 °C | 82.3 mm |
| December | -2.9 °C | 5.8 °C | 90.68 mm |
| Annual | 6 °C | 16.9 °C | 1167.4 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |