Clarkson, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.3 °C (low) to 19.4 °C (high). Annual precipitation averages 1300.5 Millimeters. Clarkson 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.2 °C | 6.1 °C | 92.2 mm |
| February | -2.8 °C | 8.6 °C | 100.08 mm |
| March | 1.2 °C | 13.7 °C | 124.46 mm |
| April | 6.6 °C | 19.8 °C | 125.98 mm |
| May | 12.3 °C | 24.7 °C | 138.18 mm |
| June | 16.8 °C | 28.9 °C | 117.86 mm |
| July | 18.9 °C | 30.6 °C | 117.6 mm |
| August | 17.7 °C | 30.1 °C | 88.39 mm |
| September | 13.7 °C | 27.1 °C | 90.17 mm |
| October | 7.4 °C | 21.2 °C | 99.57 mm |
| November | 1.4 °C | 13.9 °C | 92.96 mm |
| December | -1.8 °C | 8.2 °C | 113.03 mm |
| Annual | 7.3 °C | 19.4 °C | 1300.48 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |