Glen Lyn, Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 6 °C (low) to 18.7 °C (high). Annual precipitation averages 988.6 Millimeters. Glen Lyn is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.5 °C | 6.2 °C | 75.44 mm |
| February | -3.2 °C | 8.3 °C | 64.52 mm |
| March | 0.3 °C | 12.9 °C | 90.93 mm |
| April | 4.9 °C | 19.4 °C | 87.63 mm |
| May | 10.3 °C | 23.9 °C | 103.12 mm |
| June | 14.8 °C | 27.6 °C | 100.84 mm |
| July | 16.9 °C | 29.6 °C | 98.81 mm |
| August | 16.4 °C | 28.9 °C | 84.07 mm |
| September | 12.6 °C | 25.8 °C | 81.53 mm |
| October | 6 °C | 20 °C | 64.01 mm |
| November | 0.3 °C | 13.6 °C | 63.25 mm |
| December | -2.7 °C | 7.8 °C | 74.42 mm |
| Annual | 6 °C | 18.7 °C | 988.57 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |