Gratton, Virginia has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 5.3 °C (low) to 16.6 °C (high). Annual precipitation averages 1304.8 Millimeters. Gratton is located in USDA Plant Hardiness Zone 6b. 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 | -5.1 °C | 4.8 °C | 111 mm |
| February | -3.8 °C | 6.6 °C | 87.88 mm |
| March | -0.3 °C | 11.2 °C | 126.24 mm |
| April | 4.7 °C | 17.2 °C | 117.86 mm |
| May | 9.6 °C | 21.4 °C | 138.94 mm |
| June | 13.9 °C | 25.1 °C | 130.3 mm |
| July | 15.9 °C | 26.8 °C | 131.83 mm |
| August | 15.1 °C | 26.3 °C | 107.7 mm |
| September | 11.8 °C | 23.6 °C | 89.15 mm |
| October | 5.4 °C | 17.8 °C | 77.72 mm |
| November | -0.1 °C | 11.8 °C | 83.31 mm |
| December | -3 °C | 6.7 °C | 102.87 mm |
| Annual | 5.3 °C | 16.6 °C | 1304.8 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |