Foundryville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.9 °C (low) to 16.6 °C (high). Annual precipitation averages 1140.2 Millimeters. Foundryville is located in USDA Plant Hardiness Zone 6b. 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 | -6.9 °C | 2.4 °C | 76.2 mm |
| February | -6.1 °C | 4 °C | 58.93 mm |
| March | -2.1 °C | 8.9 °C | 78.74 mm |
| April | 3.6 °C | 16.7 °C | 97.79 mm |
| May | 9.2 °C | 22.8 °C | 99.57 mm |
| June | 14.3 °C | 27.1 °C | 121.67 mm |
| July | 16.7 °C | 29.7 °C | 120.14 mm |
| August | 15.8 °C | 28.6 °C | 108.2 mm |
| September | 11.9 °C | 24.8 °C | 124.46 mm |
| October | 5.6 °C | 18 °C | 97.54 mm |
| November | 0.5 °C | 10.9 °C | 75.95 mm |
| December | -3.6 °C | 5.1 °C | 81.03 mm |
| Annual | 4.9 °C | 16.6 °C | 1140.22 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 6b : -20.6°C to -17.8°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 |