Forest Hills, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.5 °C (low) to 20.7 °C (high). Annual precipitation averages 1367.5 Millimeters. Forest Hills 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 | -2.5 °C | 8.1 °C | 109.73 mm |
| February | -1.1 °C | 10.7 °C | 120.4 mm |
| March | 2.8 °C | 15.8 °C | 127.76 mm |
| April | 7.7 °C | 21.3 °C | 128.02 mm |
| May | 13.1 °C | 25.5 °C | 134.62 mm |
| June | 17.8 °C | 29.5 °C | 111.51 mm |
| July | 19.8 °C | 31.4 °C | 117.6 mm |
| August | 18.9 °C | 31.1 °C | 91.69 mm |
| September | 15 °C | 27.8 °C | 104.14 mm |
| October | 8.3 °C | 22.1 °C | 95.76 mm |
| November | 2.6 °C | 15.3 °C | 98.55 mm |
| December | -0.7 °C | 10 °C | 127.76 mm |
| Annual | 8.5 °C | 20.7 °C | 1367.54 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |