Port Royal, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.6 °F (low) to 62.4 °F (high). Annual precipitation averages 43.5 Inches. Port Royal 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 | 20.9 °F | 37.1 °F | 3.05 in. |
| February | 22.0 °F | 40.5 °F | 2.39 in. |
| March | 29.0 °F | 49.5 °F | 3.48 in. |
| April | 39.0 °F | 62.8 °F | 3.65 in. |
| May | 49.4 °F | 72.6 °F | 4.1 in. |
| June | 58.7 °F | 81.0 °F | 4.04 in. |
| July | 63.0 °F | 85.6 °F | 3.99 in. |
| August | 61.4 °F | 83.7 °F | 3.96 in. |
| September | 54.1 °F | 76.7 °F | 4.46 in. |
| October | 42.7 °F | 64.7 °F | 3.92 in. |
| November | 33.1 °F | 52.8 °F | 3.07 in. |
| December | 26.0 °F | 41.5 °F | 3.36 in. |
| Annual | 41.6 °F | 62.4 °F | 43.47 in. |
| 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 : 0°F to 5°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 |