Castle Shannon, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.3 °F (low) to 61.3 °F (high). Annual precipitation averages 42.1 Inches. 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 | 21.2 °F | 36.6 °F | 3.26 in. |
| February | 22.6 °F | 39.3 °F | 2.61 in. |
| March | 29.7 °F | 48.8 °F | 3.37 in. |
| April | 40.1 °F | 62.3 °F | 3.44 in. |
| May | 50.5 °F | 71.8 °F | 4.11 in. |
| June | 59.3 °F | 79.6 °F | 4.36 in. |
| July | 63.4 °F | 83.4 °F | 4.45 in. |
| August | 61.9 °F | 82.2 °F | 3.55 in. |
| September | 55.0 °F | 75.8 °F | 3.55 in. |
| October | 43.6 °F | 63.6 °F | 3.07 in. |
| November | 34.0 °F | 51.4 °F | 3.05 in. |
| December | 26.6 °F | 40.9 °F | 3.25 in. |
| Annual | 42.3 °F | 61.3 °F | 42.07 in. |
| 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 : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |