Glenmont, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.8 °C (low) to 18.5 °C (high). Annual precipitation averages 1156.7 Millimeters. Glenmont 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 | -3.6 °C | 5.7 °C | 79.25 mm |
| February | -2.8 °C | 7.4 °C | 70.1 mm |
| March | 1 °C | 12.2 °C | 101.6 mm |
| April | 6.7 °C | 19 °C | 88.14 mm |
| May | 12.2 °C | 23.5 °C | 112.78 mm |
| June | 17 °C | 28.1 °C | 115.82 mm |
| July | 19.6 °C | 30.4 °C | 111 mm |
| August | 18.7 °C | 29.3 °C | 93.98 mm |
| September | 15 °C | 25.6 °C | 112.01 mm |
| October | 8.3 °C | 19.3 °C | 97.54 mm |
| November | 2.6 °C | 13.4 °C | 80.26 mm |
| December | -1.2 °C | 7.9 °C | 94.23 mm |
| Annual | 7.8 °C | 18.5 °C | 1156.71 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |