Armagh, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 39.7 °F (low) to 59.4 °F (high). Annual precipitation averages 49 Inches. Armagh is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.9 °F | 34.8 °F | 3.97 in. |
| February | 20.3 °F | 37.9 °F | 3.18 in. |
| March | 26.9 °F | 46.7 °F | 4.0 in. |
| April | 37.5 °F | 60.4 °F | 4.2 in. |
| May | 47.8 °F | 70.3 °F | 4.35 in. |
| June | 56.3 °F | 77.4 °F | 4.73 in. |
| July | 60.3 °F | 81.0 °F | 4.89 in. |
| August | 58.9 °F | 79.8 °F | 4.42 in. |
| September | 52.4 °F | 73.4 °F | 4.09 in. |
| October | 41.3 °F | 61.9 °F | 3.54 in. |
| November | 31.5 °F | 49.8 °F | 3.73 in. |
| December | 24.5 °F | 39.2 °F | 3.88 in. |
| Annual | 39.7 °F | 59.4 °F | 48.98 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |