Winterstown, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.5 °C (low) to 17.5 °C (high). Annual precipitation averages 1186.4 Millimeters. Winterstown 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 | -4.8 °C | 4.2 °C | 84.58 mm |
| February | -3.9 °C | 6.1 °C | 70.1 mm |
| March | -0.4 °C | 10.9 °C | 104.14 mm |
| April | 5.4 °C | 17.8 °C | 93.22 mm |
| May | 10.6 °C | 22.9 °C | 103.63 mm |
| June | 15.6 °C | 27.1 °C | 104.65 mm |
| July | 18 °C | 29.5 °C | 113.79 mm |
| August | 16.8 °C | 28.6 °C | 104.14 mm |
| September | 13.3 °C | 25.2 °C | 124.46 mm |
| October | 7.1 °C | 18.8 °C | 106.43 mm |
| November | 1.9 °C | 12.4 °C | 82.3 mm |
| December | -2.2 °C | 6.6 °C | 95 mm |
| Annual | 6.5 °C | 17.5 °C | 1186.44 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 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |