Harveys Lake, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.3 °C (low) to 14.5 °C (high). Annual precipitation averages 1224 Millimeters. Harveys Lake 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 | -8.9 °C | 0.7 °C | 92.71 mm |
| February | -8.1 °C | 2.1 °C | 66.04 mm |
| March | -4.1 °C | 6.7 °C | 84.07 mm |
| April | 2 °C | 14.2 °C | 108.46 mm |
| May | 7.8 °C | 20.4 °C | 100.08 mm |
| June | 12.8 °C | 24.8 °C | 132.08 mm |
| July | 15.1 °C | 27.6 °C | 111.76 mm |
| August | 14.1 °C | 26.4 °C | 111.51 mm |
| September | 10.2 °C | 22.7 °C | 123.19 mm |
| October | 4.2 °C | 15.8 °C | 120.4 mm |
| November | -0.7 °C | 9.3 °C | 80.26 mm |
| December | -5.2 °C | 3.4 °C | 93.47 mm |
| Annual | 3.3 °C | 14.5 °C | 1224.03 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 |