Clarks Summit, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3 °C (low) to 14.4 °C (high). Annual precipitation averages 1176 Millimeters. Clarks Summit 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | 0.3 °C | 82.04 mm |
| February | -8.6 °C | 1.8 °C | 64.52 mm |
| March | -4.4 °C | 6.4 °C | 83.82 mm |
| April | 1.5 °C | 14.3 °C | 99.06 mm |
| May | 7.4 °C | 20.5 °C | 102.36 mm |
| June | 12.6 °C | 24.9 °C | 126.75 mm |
| July | 14.9 °C | 27.4 °C | 113.28 mm |
| August | 14.1 °C | 26.3 °C | 114.55 mm |
| September | 10.1 °C | 22.6 °C | 111.51 mm |
| October | 4 °C | 15.7 °C | 111.76 mm |
| November | -1 °C | 9 °C | 78.99 mm |
| December | -5.5 °C | 3.1 °C | 87.38 mm |
| Annual | 3 °C | 14.4 °C | 1176.02 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |