Darnestown, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.5 °C (low) to 18.5 °C (high). Annual precipitation averages 1144.3 Millimeters. Darnestown is located in USDA Plant Hardiness Zone 7b. 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 | -3.8 °C | 5.7 °C | 77.47 mm |
| February | -2.9 °C | 7.4 °C | 68.83 mm |
| March | 0.8 °C | 12.2 °C | 98.55 mm |
| April | 6.4 °C | 18.8 °C | 86.87 mm |
| May | 11.8 °C | 23.4 °C | 113.28 mm |
| June | 16.7 °C | 28.1 °C | 114.3 mm |
| July | 19.4 °C | 30.4 °C | 106.43 mm |
| August | 18.4 °C | 29.5 °C | 89.41 mm |
| September | 14.7 °C | 25.7 °C | 113.79 mm |
| October | 7.9 °C | 19.4 °C | 99.57 mm |
| November | 2.4 °C | 13.3 °C | 83.31 mm |
| December | -1.4 °C | 7.8 °C | 92.46 mm |
| Annual | 7.5 °C | 18.5 °C | 1144.27 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 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |