Mount Holly Springs, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.2 °C (low) to 17.2 °C (high). Annual precipitation averages 1146.1 Millimeters. Mount Holly Springs is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.4 °C | 3.4 °C | 82.55 mm |
| February | -4.7 °C | 5.1 °C | 68.33 mm |
| March | -0.7 °C | 10 °C | 97.03 mm |
| April | 5 °C | 17.1 °C | 97.54 mm |
| May | 10.7 °C | 22.6 °C | 109.73 mm |
| June | 15.7 °C | 27.4 °C | 105.92 mm |
| July | 18.2 °C | 30.2 °C | 104.14 mm |
| August | 17.2 °C | 28.9 °C | 92.46 mm |
| September | 13.2 °C | 25.1 °C | 118.62 mm |
| October | 6.9 °C | 18.6 °C | 100.58 mm |
| November | 1.3 °C | 11.9 °C | 81.03 mm |
| December | -2.8 °C | 5.7 °C | 88.14 mm |
| Annual | 6.2 °C | 17.2 °C | 1146.07 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |