Hardin, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.8 °C (low) to 20.5 °C (high). Annual precipitation averages 1369.1 Millimeters. Hardin is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.7 °C | 7.3 °C | 100.33 mm |
| February | -1.2 °C | 9.8 °C | 111.76 mm |
| March | 3.3 °C | 15.3 °C | 126.49 mm |
| April | 8.3 °C | 21.3 °C | 132.59 mm |
| May | 13.8 °C | 25.7 °C | 147.07 mm |
| June | 18.5 °C | 29.9 °C | 124.21 mm |
| July | 20.5 °C | 31.7 °C | 111.76 mm |
| August | 19.3 °C | 31.6 °C | 88.14 mm |
| September | 15.1 °C | 28.2 °C | 93.47 mm |
| October | 8.7 °C | 21.8 °C | 97.28 mm |
| November | 2.8 °C | 14.8 °C | 106.43 mm |
| December | -1.2 °C | 9.1 °C | 129.54 mm |
| Annual | 8.8 °C | 20.5 °C | 1369.07 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |