Langhorne, Pennsylvania has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.4 °C (low) to 17.8 °C (high). Annual precipitation averages 1239 Millimeters. Langhorne is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.3 °C | 4.7 °C | 89.92 mm |
| February | -3.6 °C | 6.2 °C | 71.37 mm |
| March | 0.3 °C | 10.6 °C | 111.76 mm |
| April | 5.9 °C | 17.3 °C | 93.22 mm |
| May | 11.4 °C | 22.6 °C | 107.44 mm |
| June | 16.7 °C | 27.6 °C | 111 mm |
| July | 19.6 °C | 30.2 °C | 122.68 mm |
| August | 18.6 °C | 29.3 °C | 126.75 mm |
| September | 14.6 °C | 25.7 °C | 106.68 mm |
| October | 8.1 °C | 19 °C | 101.85 mm |
| November | 2.6 °C | 12.9 °C | 83.82 mm |
| December | -1.6 °C | 7.3 °C | 112.52 mm |
| Annual | 7.4 °C | 17.8 °C | 1239.01 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |