Forksville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.8 °C (low) to 14.6 °C (high). Annual precipitation averages 1156.7 Millimeters. Forksville is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.1 °C | 0.7 °C | 83.31 mm |
| February | -8.6 °C | 2.1 °C | 61.21 mm |
| March | -4.6 °C | 6.8 °C | 86.36 mm |
| April | 1.2 °C | 14.5 °C | 98.81 mm |
| May | 7.1 °C | 20.7 °C | 98.04 mm |
| June | 12.2 °C | 25 °C | 113.79 mm |
| July | 14.7 °C | 27.4 °C | 114.3 mm |
| August | 13.7 °C | 26.6 °C | 106.43 mm |
| September | 9.7 °C | 22.7 °C | 118.87 mm |
| October | 3.7 °C | 15.9 °C | 104.65 mm |
| November | -1.2 °C | 9.2 °C | 83.06 mm |
| December | -5.4 °C | 3.3 °C | 87.88 mm |
| Annual | 2.8 °C | 14.6 °C | 1156.71 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°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 |