Mount Briar, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.5 °C (low) to 18.2 °C (high). Annual precipitation averages 1089.9 Millimeters. Mount Briar 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.4 °C | 5.1 °C | 78.23 mm |
| February | -3.7 °C | 7.1 °C | 62.23 mm |
| March | 0.3 °C | 11.7 °C | 92.71 mm |
| April | 5.5 °C | 18.3 °C | 91.69 mm |
| May | 10.7 °C | 23.2 °C | 112.27 mm |
| June | 15.7 °C | 27.9 °C | 99.31 mm |
| July | 18 °C | 30.4 °C | 101.35 mm |
| August | 17 °C | 29.5 °C | 85.85 mm |
| September | 13.2 °C | 25.6 °C | 108.97 mm |
| October | 7.2 °C | 19.3 °C | 89.66 mm |
| November | 1.6 °C | 12.9 °C | 80.26 mm |
| December | -2.6 °C | 7.1 °C | 87.38 mm |
| Annual | 6.5 °C | 18.2 °C | 1089.91 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |