Orrtanna, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.1 °C (low) to 17.1 °C (high). Annual precipitation averages 1188.5 Millimeters. Orrtanna 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 | 3.6 °C | 90.68 mm |
| February | -4.8 °C | 5.3 °C | 70.87 mm |
| March | -0.8 °C | 10.1 °C | 102.62 mm |
| April | 4.9 °C | 17.1 °C | 103.89 mm |
| May | 10.4 °C | 22.3 °C | 114.3 mm |
| June | 15.4 °C | 27.1 °C | 102.62 mm |
| July | 17.9 °C | 29.7 °C | 99.31 mm |
| August | 16.9 °C | 28.6 °C | 99.31 mm |
| September | 13.1 °C | 24.9 °C | 122.68 mm |
| October | 6.7 °C | 18.4 °C | 102.36 mm |
| November | 1.3 °C | 11.9 °C | 84.58 mm |
| December | -2.8 °C | 5.9 °C | 95.25 mm |
| Annual | 6.1 °C | 17.1 °C | 1188.47 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 |