Derwood, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.6 °C (low) to 18.3 °C (high). Annual precipitation averages 1148.6 Millimeters. Derwood is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.7 °C | 5.5 °C | 79.25 mm |
| February | -2.8 °C | 7.3 °C | 70.1 mm |
| March | 0.9 °C | 11.9 °C | 100.58 mm |
| April | 6.4 °C | 18.6 °C | 86.61 mm |
| May | 11.9 °C | 23.3 °C | 113.03 mm |
| June | 16.7 °C | 27.9 °C | 114.05 mm |
| July | 19.3 °C | 30.3 °C | 108.46 mm |
| August | 18.3 °C | 29.2 °C | 90.42 mm |
| September | 14.7 °C | 25.5 °C | 111.76 mm |
| October | 8.1 °C | 19.2 °C | 98.3 mm |
| November | 2.7 °C | 13.2 °C | 83.57 mm |
| December | -1.3 °C | 7.7 °C | 92.46 mm |
| Annual | 7.6 °C | 18.3 °C | 1148.59 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |