Fort Washington, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9 °C (low) to 19.4 °C (high). Annual precipitation averages 1150.6 Millimeters. Fort Washington is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.5 °C | 6.8 °C | 77.72 mm |
| February | -1.6 °C | 8.7 °C | 68.83 mm |
| March | 2.2 °C | 13.2 °C | 97.54 mm |
| April | 7.8 °C | 19.6 °C | 86.36 mm |
| May | 13.1 °C | 24.2 °C | 111.76 mm |
| June | 18.2 °C | 28.8 °C | 114.3 mm |
| July | 20.9 °C | 31.3 °C | 116.08 mm |
| August | 20 °C | 30.3 °C | 94.23 mm |
| September | 16.3 °C | 26.6 °C | 110.49 mm |
| October | 9.7 °C | 20.3 °C | 98.81 mm |
| November | 3.9 °C | 14.2 °C | 79.5 mm |
| December | -0.1 °C | 9 °C | 95 mm |
| Annual | 9 °C | 19.4 °C | 1150.62 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 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 |