Milroy, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.3 °C (low) to 16 °C (high). Annual precipitation averages 1016.3 Millimeters. Milroy 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.2 °C | 1.8 °C | 75.18 mm |
| February | -6.6 °C | 3.7 °C | 59.44 mm |
| March | -2.8 °C | 8.7 °C | 85.6 mm |
| April | 2.9 °C | 16.2 °C | 84.33 mm |
| May | 8.7 °C | 22 °C | 95.25 mm |
| June | 13.8 °C | 26.4 °C | 88.65 mm |
| July | 16.1 °C | 28.8 °C | 85.85 mm |
| August | 15.2 °C | 27.8 °C | 82.3 mm |
| September | 11.1 °C | 23.9 °C | 110.24 mm |
| October | 4.9 °C | 17.3 °C | 87.88 mm |
| November | -0.3 °C | 10.6 °C | 77.98 mm |
| December | -4.2 °C | 4.3 °C | 83.57 mm |
| Annual | 4.3 °C | 16 °C | 1016.27 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |