Gettysburg, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6 °C (low) to 17.5 °C (high). Annual precipitation averages 1142.5 Millimeters. Gettysburg 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 | 4 °C | 83.57 mm |
| February | -4.7 °C | 5.7 °C | 68.07 mm |
| March | -0.8 °C | 10.5 °C | 97.03 mm |
| April | 4.9 °C | 17.3 °C | 91.69 mm |
| May | 10.3 °C | 22.7 °C | 106.43 mm |
| June | 15.5 °C | 27.4 °C | 105.16 mm |
| July | 17.9 °C | 30.1 °C | 100.08 mm |
| August | 16.9 °C | 29 °C | 96.77 mm |
| September | 13 °C | 25.3 °C | 125.98 mm |
| October | 6.5 °C | 18.7 °C | 98.55 mm |
| November | 1.1 °C | 12.4 °C | 80.52 mm |
| December | -2.8 °C | 6.3 °C | 88.65 mm |
| Annual | 6 °C | 17.5 °C | 1142.5 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 |