Harleigh, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.8 °F (low) to 57.6 °F (high). Annual precipitation averages 51.6 Inches. Harleigh is located in USDA Plant Hardiness Zone 6b. 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 | 17.4 °F | 33.1 °F | 3.72 in. |
| February | 18.7 °F | 36.0 °F | 2.86 in. |
| March | 25.9 °F | 44.2 °F | 3.77 in. |
| April | 36.5 °F | 57.5 °F | 4.33 in. |
| May | 46.9 °F | 68.1 °F | 4.26 in. |
| June | 55.5 °F | 75.8 °F | 5.3 in. |
| July | 60.0 °F | 80.2 °F | 4.72 in. |
| August | 58.0 °F | 78.2 °F | 4.86 in. |
| September | 51.3 °F | 71.7 °F | 5.27 in. |
| October | 40.8 °F | 60.5 °F | 4.85 in. |
| November | 31.3 °F | 48.3 °F | 3.7 in. |
| December | 23.2 °F | 38.1 °F | 3.98 in. |
| Annual | 38.8 °F | 57.6 °F | 51.62 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |