Fincastle, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.5 °C (low) to 20.1 °C (high). Annual precipitation averages 1403.1 Millimeters. Fincastle 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 | -3.2 °C | 7.7 °C | 122.68 mm |
| February | -1.6 °C | 10.2 °C | 121.92 mm |
| March | 1.7 °C | 15.3 °C | 138.68 mm |
| April | 6.5 °C | 20.8 °C | 128.52 mm |
| May | 12.1 °C | 25.3 °C | 113.79 mm |
| June | 16.4 °C | 28.8 °C | 122.94 mm |
| July | 18.7 °C | 30.3 °C | 140.21 mm |
| August | 17.9 °C | 29.9 °C | 103.38 mm |
| September | 14.4 °C | 27.3 °C | 93.98 mm |
| October | 7.4 °C | 21.3 °C | 76.2 mm |
| November | 1.4 °C | 14.8 °C | 102.36 mm |
| December | -1.2 °C | 9.5 °C | 138.43 mm |
| Annual | 7.5 °C | 20.1 °C | 1403.09 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |