Castle Shannon, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.7 °C (low) to 16.3 °C (high). Annual precipitation averages 1068.6 Millimeters. Castle Shannon is located in USDA Plant Hardiness Zone 6b. 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 | -6 °C | 2.6 °C | 82.8 mm |
| February | -5.2 °C | 4.1 °C | 66.29 mm |
| March | -1.3 °C | 9.3 °C | 85.6 mm |
| April | 4.5 °C | 16.8 °C | 87.38 mm |
| May | 10.3 °C | 22.1 °C | 104.39 mm |
| June | 15.2 °C | 26.4 °C | 110.74 mm |
| July | 17.4 °C | 28.6 °C | 113.03 mm |
| August | 16.6 °C | 27.9 °C | 90.17 mm |
| September | 12.8 °C | 24.3 °C | 90.17 mm |
| October | 6.4 °C | 17.6 °C | 77.98 mm |
| November | 1.1 °C | 10.8 °C | 77.47 mm |
| December | -3 °C | 4.9 °C | 82.55 mm |
| Annual | 5.7 °C | 16.3 °C | 1068.57 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |