Palmyra, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.6 °C (low) to 17.6 °C (high). Annual precipitation averages 1007.9 Millimeters. Palmyra is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.3 °C | 2 °C | 48.01 mm |
| February | -5.3 °C | 4.8 °C | 53.34 mm |
| March | -0.1 °C | 11.2 °C | 66.29 mm |
| April | 6.1 °C | 18.1 °C | 106.17 mm |
| May | 12.2 °C | 23.6 °C | 125.22 mm |
| June | 17.6 °C | 28.6 °C | 110.49 mm |
| July | 19.5 °C | 30.7 °C | 104.14 mm |
| August | 18.3 °C | 29.9 °C | 100.58 mm |
| September | 13.7 °C | 26.4 °C | 87.88 mm |
| October | 7.3 °C | 19.4 °C | 83.82 mm |
| November | 0.9 °C | 11.4 °C | 70.87 mm |
| December | -4.3 °C | 4.6 °C | 51.05 mm |
| Annual | 6.6 °C | 17.6 °C | 1007.86 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |