Mechanicsville, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.1 °C (low) to 19.7 °C (high). Annual precipitation averages 1187.7 Millimeters. Mechanicsville 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 °C | 7.4 °C | 80.77 mm |
| February | -2.1 °C | 9.4 °C | 71.37 mm |
| March | 1.4 °C | 13.9 °C | 102.87 mm |
| April | 6.9 °C | 20.2 °C | 84.07 mm |
| May | 12.2 °C | 24.3 °C | 109.47 mm |
| June | 17.1 °C | 28.7 °C | 108.97 mm |
| July | 19.7 °C | 30.9 °C | 112.52 mm |
| August | 18.8 °C | 29.9 °C | 117.09 mm |
| September | 15.2 °C | 26.4 °C | 114.55 mm |
| October | 8.7 °C | 20.5 °C | 104.9 mm |
| November | 3 °C | 14.8 °C | 82.55 mm |
| December | -0.7 °C | 9.6 °C | 98.55 mm |
| Annual | 8.1 °C | 19.7 °C | 1187.68 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |