Exton, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.1 °C (low) to 17.4 °C (high). Annual precipitation averages 1248.9 Millimeters. Exton 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.6 °C | 4.1 °C | 90.68 mm |
| February | -5.1 °C | 5.4 °C | 74.42 mm |
| March | -1.1 °C | 10.3 °C | 107.7 mm |
| April | 4.7 °C | 17.2 °C | 96.52 mm |
| May | 10.2 °C | 22.5 °C | 100.08 mm |
| June | 15.4 °C | 27.4 °C | 114.81 mm |
| July | 18.3 °C | 29.8 °C | 118.36 mm |
| August | 17.4 °C | 29 °C | 111 mm |
| September | 13.2 °C | 25.4 °C | 128.78 mm |
| October | 6.7 °C | 18.7 °C | 112.01 mm |
| November | 1.2 °C | 12.3 °C | 84.58 mm |
| December | -2.6 °C | 6.6 °C | 109.98 mm |
| Annual | 6.1 °C | 17.4 °C | 1248.92 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |