Herald Harbor, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.2 °C (low) to 18.6 °C (high). Annual precipitation averages 1176.8 Millimeters. Herald Harbor 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 | -2.5 °C | 5.9 °C | 80.52 mm |
| February | -1.8 °C | 7.2 °C | 70.36 mm |
| March | 2.1 °C | 11.6 °C | 106.93 mm |
| April | 7.9 °C | 18.4 °C | 88.39 mm |
| May | 13.3 °C | 23.3 °C | 107.95 mm |
| June | 18.6 °C | 28.3 °C | 114.3 mm |
| July | 21.3 °C | 30.7 °C | 113.79 mm |
| August | 20.4 °C | 29.7 °C | 101.35 mm |
| September | 16.8 °C | 26.1 °C | 116.84 mm |
| October | 10.2 °C | 19.8 °C | 99.82 mm |
| November | 4.3 °C | 13.4 °C | 79.5 mm |
| December | 0.1 °C | 8.3 °C | 97.03 mm |
| Annual | 9.2 °C | 18.6 °C | 1176.78 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 7b : -15°C to -12.2°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |