Fallston, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7 °C (low) to 18.8 °C (high). Annual precipitation averages 1269.5 Millimeters. Fallston 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 | -4.6 °C | 5.7 °C | 88.39 mm |
| February | -3.8 °C | 7.3 °C | 71.63 mm |
| March | -0.1 °C | 12 °C | 113.28 mm |
| April | 5.8 °C | 18.9 °C | 95.76 mm |
| May | 11.2 °C | 24 °C | 110.49 mm |
| June | 16.2 °C | 28.6 °C | 117.09 mm |
| July | 19.1 °C | 30.9 °C | 120.14 mm |
| August | 17.9 °C | 30.1 °C | 119.13 mm |
| September | 14.2 °C | 26.6 °C | 120.9 mm |
| October | 7.7 °C | 20.3 °C | 117.86 mm |
| November | 1.9 °C | 13.6 °C | 87.38 mm |
| December | -2.1 °C | 7.9 °C | 107.44 mm |
| Annual | 7 °C | 18.8 °C | 1269.49 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 |