Forest Glen, Maryland has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 46.8 °F (low) to 66.1 °F (high). Annual precipitation averages 45.7 Inches. Forest Glen 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 | 26.4 °F | 43.1 °F | 3.11 in. |
| February | 27.8 °F | 46.3 °F | 2.75 in. |
| March | 34.5 °F | 54.8 °F | 3.99 in. |
| April | 44.5 °F | 66.9 °F | 3.47 in. |
| May | 54.4 °F | 75.2 °F | 4.46 in. |
| June | 63.3 °F | 83.4 °F | 4.58 in. |
| July | 68.0 °F | 87.5 °F | 4.47 in. |
| August | 66.4 °F | 85.7 °F | 3.7 in. |
| September | 59.8 °F | 78.9 °F | 4.43 in. |
| October | 47.9 °F | 67.6 °F | 3.85 in. |
| November | 37.5 °F | 56.8 °F | 3.16 in. |
| December | 30.7 °F | 47.0 °F | 3.71 in. |
| Annual | 46.8 °F | 66.1 °F | 45.68 in. |
| 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 : 5°F to 10°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |