Clark, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.9 °F (low) to 61.2 °F (high). Annual precipitation averages 42.3 Inches. Clark 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 | 19.0 °F | 35.4 °F | 2.98 in. |
| February | 19.7 °F | 38.4 °F | 2.31 in. |
| March | 27.3 °F | 47.6 °F | 3.0 in. |
| April | 37.3 °F | 61.6 °F | 3.86 in. |
| May | 47.6 °F | 72.2 °F | 3.87 in. |
| June | 56.6 °F | 80.4 °F | 4.53 in. |
| July | 60.7 °F | 84.1 °F | 4.51 in. |
| August | 58.9 °F | 82.7 °F | 3.69 in. |
| September | 52.3 °F | 76.4 °F | 4.05 in. |
| October | 41.4 °F | 64.1 °F | 3.3 in. |
| November | 32.9 °F | 51.0 °F | 3.06 in. |
| December | 25.2 °F | 40.2 °F | 3.18 in. |
| Annual | 39.9 °F | 61.2 °F | 42.34 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |