Hartstown, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.8 °C (low) to 14.8 °C (high). Annual precipitation averages 1148.1 Millimeters. Hartstown 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 | -8.1 °C | 0.8 °C | 84.58 mm |
| February | -7.9 °C | 2.2 °C | 59.18 mm |
| March | -3.7 °C | 7.2 °C | 78.74 mm |
| April | 2.2 °C | 14.7 °C | 101.85 mm |
| May | 8.2 °C | 20.8 °C | 102.62 mm |
| June | 13.1 °C | 25.3 °C | 123.95 mm |
| July | 15.4 °C | 27.4 °C | 118.62 mm |
| August | 14.4 °C | 26.5 °C | 100.08 mm |
| September | 10.8 °C | 23.1 °C | 109.73 mm |
| October | 5.1 °C | 16.4 °C | 97.03 mm |
| November | 0.1 °C | 9.5 °C | 85.09 mm |
| December | -4.4 °C | 3.5 °C | 86.61 mm |
| Annual | 3.8 °C | 14.8 °C | 1148.08 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |