Grayson, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 42 °F (low) to 66.4 °F (high). Annual precipitation averages 45.7 Inches. Grayson is located in USDA Plant Hardiness Zone 6b. 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 | 22.0 °F | 42.3 °F | 3.16 in. |
| February | 24.1 °F | 46.3 °F | 3.2 in. |
| March | 30.0 °F | 55.9 °F | 4.26 in. |
| April | 39.9 °F | 68.4 °F | 4.16 in. |
| May | 50.5 °F | 76.3 °F | 4.78 in. |
| June | 59.2 °F | 83.3 °F | 4.45 in. |
| July | 63.5 °F | 86.5 °F | 5.08 in. |
| August | 61.7 °F | 85.7 °F | 3.65 in. |
| September | 54.2 °F | 80.2 °F | 3.32 in. |
| October | 41.7 °F | 69.4 °F | 2.93 in. |
| November | 31.3 °F | 56.6 °F | 2.94 in. |
| December | 26.3 °F | 46.2 °F | 3.77 in. |
| Annual | 42 °F | 66.4 °F | 45.7 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |