Mountain Lake Park, Maryland has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.9 °C (low) to 14.8 °C (high). Annual precipitation averages 1280.9 Millimeters. Mountain Lake Park is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.9 °C | 1.8 °C | 96.27 mm |
| February | -7 °C | 3.8 °C | 95.25 mm |
| March | -3.7 °C | 8.2 °C | 111.51 mm |
| April | 1.7 °C | 15.4 °C | 113.54 mm |
| May | 7.3 °C | 20 °C | 134.37 mm |
| June | 11.9 °C | 24.1 °C | 128.78 mm |
| July | 14.1 °C | 26.1 °C | 128.27 mm |
| August | 13.1 °C | 25.4 °C | 105.66 mm |
| September | 9.2 °C | 22.3 °C | 97.79 mm |
| October | 3.2 °C | 16.2 °C | 87.88 mm |
| November | -1.9 °C | 9.6 °C | 83.06 mm |
| December | -5.3 °C | 4.2 °C | 98.55 mm |
| Annual | 2.9 °C | 14.8 °C | 1280.93 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |