Jellico, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.1 °C (low) to 19.9 °C (high). Annual precipitation averages 1382.8 Millimeters. Jellico is located in USDA Plant Hardiness Zone 7a. 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 | -3.5 °C | 7.5 °C | 118.36 mm |
| February | -2.1 °C | 9.9 °C | 121.41 mm |
| March | 1.2 °C | 15.1 °C | 132.84 mm |
| April | 5.9 °C | 20.8 °C | 128.27 mm |
| May | 11.6 °C | 25.1 °C | 119.13 mm |
| June | 16 °C | 28.9 °C | 125.98 mm |
| July | 18.3 °C | 30.2 °C | 145.03 mm |
| August | 17.5 °C | 29.7 °C | 99.57 mm |
| September | 13.8 °C | 26.8 °C | 91.69 mm |
| October | 6.9 °C | 21 °C | 73.91 mm |
| November | 0.9 °C | 14.7 °C | 93.73 mm |
| December | -1.5 °C | 9.5 °C | 132.84 mm |
| Annual | 7.1 °C | 19.9 °C | 1382.76 mm |
| 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |