Signal Mountain, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.9 °C (low) to 19.2 °C (high). Annual precipitation averages 1721.6 Millimeters. Signal Mountain is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.9 °C | 7.3 °C | 161.29 mm |
| February | -0.2 °C | 9.7 °C | 151.13 mm |
| March | 3.7 °C | 14.5 °C | 162.05 mm |
| April | 8.6 °C | 20 °C | 144.02 mm |
| May | 13.2 °C | 24.1 °C | 132.08 mm |
| June | 17.2 °C | 27.6 °C | 138.94 mm |
| July | 19 °C | 29.3 °C | 142.24 mm |
| August | 18.6 °C | 29 °C | 110.74 mm |
| September | 15.3 °C | 26.1 °C | 136.4 mm |
| October | 9.2 °C | 20.3 °C | 105.16 mm |
| November | 4 °C | 13.8 °C | 150.37 mm |
| December | 0.3 °C | 8.8 °C | 187.2 mm |
| Annual | 8.9 °C | 19.2 °C | 1721.62 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 |