New Wilmington, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.1 °C (low) to 16 °C (high). Annual precipitation averages 1082.6 Millimeters. New Wilmington is located in USDA Plant Hardiness Zone 6a. 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 | -7.5 °C | 1.8 °C | 78.74 mm |
| February | -7.2 °C | 3.4 °C | 61.47 mm |
| March | -2.9 °C | 8.7 °C | 79.25 mm |
| April | 2.7 °C | 16.2 °C | 97.54 mm |
| May | 8.4 °C | 21.9 °C | 97.54 mm |
| June | 13.4 °C | 26.4 °C | 115.82 mm |
| July | 15.6 °C | 28.7 °C | 116.08 mm |
| August | 14.7 °C | 27.9 °C | 94.23 mm |
| September | 10.9 °C | 24.4 °C | 100.08 mm |
| October | 4.9 °C | 17.6 °C | 82.55 mm |
| November | 0.1 °C | 10.4 °C | 77.98 mm |
| December | -4.1 °C | 4.4 °C | 81.28 mm |
| Annual | 4.1 °C | 16 °C | 1082.56 mm |
| 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 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 | Dfb - Humid Continental Mild Summer, Wet All Year |