Knoxville, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.2 °C (low) to 21.1 °C (high). Annual precipitation averages 1331.5 Millimeters. Knoxville 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 | -1.7 °C | 8.8 °C | 123.7 mm |
| February | 0 °C | 11.3 °C | 116.33 mm |
| March | 3.5 °C | 16.3 °C | 126.75 mm |
| April | 8.2 °C | 21.6 °C | 117.86 mm |
| May | 13.6 °C | 25.9 °C | 109.47 mm |
| June | 17.9 °C | 29.7 °C | 115.06 mm |
| July | 20.2 °C | 31.3 °C | 140.46 mm |
| August | 19.6 °C | 31.1 °C | 81.53 mm |
| September | 16.2 °C | 28.4 °C | 87.38 mm |
| October | 9.3 °C | 22.4 °C | 81.03 mm |
| November | 2.8 °C | 15.7 °C | 100.58 mm |
| December | 0.2 °C | 10.7 °C | 131.32 mm |
| Annual | 9.2 °C | 21.1 °C | 1331.47 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 |