Lebanon, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.9 °C (low) to 17 °C (high). Annual precipitation averages 1186.9 Millimeters. Lebanon is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.9 °C | 3.2 °C | 82.04 mm |
| February | -5.3 °C | 4.8 °C | 63.75 mm |
| March | -1.1 °C | 9.8 °C | 98.04 mm |
| April | 4.6 °C | 16.9 °C | 96.77 mm |
| May | 10.3 °C | 22.4 °C | 97.79 mm |
| June | 15.5 °C | 27.2 °C | 116.84 mm |
| July | 17.9 °C | 29.8 °C | 116.33 mm |
| August | 16.9 °C | 28.7 °C | 106.43 mm |
| September | 13 °C | 24.9 °C | 122.43 mm |
| October | 6.6 °C | 18.2 °C | 108.46 mm |
| November | 1.1 °C | 11.8 °C | 83.06 mm |
| December | -2.9 °C | 5.8 °C | 95 mm |
| Annual | 5.9 °C | 17 °C | 1186.94 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 |