Greenback, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9 °C (low) to 21.1 °C (high). Annual precipitation averages 1446.5 Millimeters. Greenback is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.7 °C | 8.9 °C | 128.52 mm |
| February | -0.2 °C | 11.3 °C | 127 mm |
| March | 3.5 °C | 16.3 °C | 135.89 mm |
| April | 8.2 °C | 21.6 °C | 133.6 mm |
| May | 13.3 °C | 25.9 °C | 116.59 mm |
| June | 17.8 °C | 29.6 °C | 122.94 mm |
| July | 19.9 °C | 31.2 °C | 149.35 mm |
| August | 19.3 °C | 30.8 °C | 97.28 mm |
| September | 15.8 °C | 28.3 °C | 94.23 mm |
| October | 9 °C | 22.3 °C | 86.87 mm |
| November | 2.9 °C | 15.8 °C | 117.35 mm |
| December | 0.2 °C | 10.7 °C | 136.91 mm |
| Annual | 9 °C | 21.1 °C | 1446.53 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |