Chestertown, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.8 °C (low) to 18.9 °C (high). Annual precipitation averages 1162.8 Millimeters. Chestertown is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.4 °C | 5.9 °C | 83.82 mm |
| February | -2.8 °C | 7.4 °C | 70.87 mm |
| March | 1 °C | 11.8 °C | 103.63 mm |
| April | 6.6 °C | 18.6 °C | 90.17 mm |
| May | 11.9 °C | 23.7 °C | 103.63 mm |
| June | 17.1 °C | 28.6 °C | 111.76 mm |
| July | 19.7 °C | 30.9 °C | 110.49 mm |
| August | 18.7 °C | 30.1 °C | 102.87 mm |
| September | 14.9 °C | 26.7 °C | 109.47 mm |
| October | 8.3 °C | 20.3 °C | 101.85 mm |
| November | 2.9 °C | 13.8 °C | 78.23 mm |
| December | -1.1 °C | 8.5 °C | 96.01 mm |
| Annual | 7.8 °C | 18.9 °C | 1162.8 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |