Hornsby, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.7 °C (low) to 21.9 °C (high). Annual precipitation averages 1442.2 Millimeters. Hornsby 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 Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.4 °C | 9.6 °C | 114.3 mm |
| February | 0.4 °C | 12.2 °C | 128.78 mm |
| March | 4.3 °C | 17.2 °C | 145.54 mm |
| April | 9.2 °C | 22.4 °C | 141.48 mm |
| May | 14.6 °C | 26.6 °C | 136.91 mm |
| June | 19.2 °C | 30.6 °C | 114.05 mm |
| July | 21.1 °C | 32.3 °C | 114.55 mm |
| August | 20.1 °C | 32.1 °C | 91.44 mm |
| September | 16 °C | 28.9 °C | 103.63 mm |
| October | 9.2 °C | 23.3 °C | 101.85 mm |
| November | 3.3 °C | 16.7 °C | 107.19 mm |
| December | 0.2 °C | 11.2 °C | 142.49 mm |
| Annual | 9.7 °C | 21.9 °C | 1442.21 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |