New Washington, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.2 °C (low) to 14.4 °C (high). Annual precipitation averages 1214.1 Millimeters. New Washington 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 | -8.4 °C | 0.5 °C | 98.3 mm |
| February | -7.8 °C | 2.2 °C | 75.44 mm |
| March | -4.1 °C | 7.1 °C | 101.09 mm |
| April | 1.8 °C | 14.7 °C | 104.65 mm |
| May | 7.7 °C | 20.5 °C | 111.51 mm |
| June | 12.4 °C | 24.6 °C | 113.79 mm |
| July | 14.7 °C | 26.8 °C | 112.52 mm |
| August | 13.9 °C | 26.1 °C | 108.2 mm |
| September | 10.1 °C | 22.3 °C | 106.93 mm |
| October | 4.1 °C | 15.8 °C | 87.38 mm |
| November | -1.3 °C | 8.8 °C | 96.52 mm |
| December | -5.2 °C | 2.8 °C | 97.79 mm |
| Annual | 3.2 °C | 14.4 °C | 1214.12 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |