Fairfield, Kentucky has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.4 °C (low) to 19.5 °C (high). Annual precipitation averages 1273.3 Millimeters. Fairfield 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 | -4.3 °C | 5.8 °C | 90.93 mm |
| February | -2.7 °C | 8.3 °C | 94.74 mm |
| March | 1.2 °C | 13.6 °C | 120.4 mm |
| April | 6.7 °C | 19.9 °C | 123.44 mm |
| May | 12.4 °C | 24.8 °C | 136.91 mm |
| June | 16.9 °C | 29.3 °C | 129.79 mm |
| July | 18.9 °C | 30.8 °C | 113.54 mm |
| August | 17.9 °C | 30.7 °C | 84.07 mm |
| September | 14 °C | 27.6 °C | 91.69 mm |
| October | 7.6 °C | 21.1 °C | 91.69 mm |
| November | 1.7 °C | 13.7 °C | 90.42 mm |
| December | -1.9 °C | 7.8 °C | 105.66 mm |
| Annual | 7.4 °C | 19.5 °C | 1273.28 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°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 |