Perry Hall, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.3 °C (low) to 18.8 °C (high). Annual precipitation averages 1251 Millimeters. Perry Hall is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.3 °C | 5.9 °C | 87.63 mm |
| February | -2.6 °C | 7.4 °C | 73.41 mm |
| March | 1.2 °C | 12 °C | 111.25 mm |
| April | 7.1 °C | 18.7 °C | 94.74 mm |
| May | 12.4 °C | 23.7 °C | 109.22 mm |
| June | 17.6 °C | 28.6 °C | 116.08 mm |
| July | 20.4 °C | 31 °C | 115.32 mm |
| August | 19.4 °C | 29.9 °C | 108.97 mm |
| September | 15.7 °C | 26.4 °C | 123.95 mm |
| October | 9.2 °C | 20 °C | 117.09 mm |
| November | 3.2 °C | 13.7 °C | 86.87 mm |
| December | -0.8 °C | 8.2 °C | 106.43 mm |
| Annual | 8.3 °C | 18.8 °C | 1250.96 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |