Thurmont, Maryland has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.7 °C (low) to 18 °C (high). Annual precipitation averages 1147.8 Millimeters. Thurmont is located in USDA Plant Hardiness Zone 7a. 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 | 4.6 °C | 85.34 mm |
| February | -3.8 °C | 6.5 °C | 65.79 mm |
| March | -0.1 °C | 11.3 °C | 96.27 mm |
| April | 5.5 °C | 18.2 °C | 103.12 mm |
| May | 10.9 °C | 23.1 °C | 109.22 mm |
| June | 15.9 °C | 27.8 °C | 103.63 mm |
| July | 18.5 °C | 30.3 °C | 99.57 mm |
| August | 17.4 °C | 29.2 °C | 90.68 mm |
| September | 13.6 °C | 25.6 °C | 120.9 mm |
| October | 7.4 °C | 19.2 °C | 96.52 mm |
| November | 1.7 °C | 12.7 °C | 84.84 mm |
| December | -2.1 °C | 6.9 °C | 91.95 mm |
| Annual | 6.7 °C | 18 °C | 1147.83 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |