Seymour, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.2 °C (low) to 20.4 °C (high). Annual precipitation averages 1296.9 Millimeters. Seymour 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 | -2.4 °C | 8.4 °C | 123.7 mm |
| February | -0.8 °C | 10.8 °C | 113.79 mm |
| March | 2.7 °C | 15.8 °C | 124.71 mm |
| April | 7.2 °C | 21 °C | 115.06 mm |
| May | 12.4 °C | 25.2 °C | 105.16 mm |
| June | 16.8 °C | 28.8 °C | 105.66 mm |
| July | 18.9 °C | 30.3 °C | 131.57 mm |
| August | 18.3 °C | 30.1 °C | 79.76 mm |
| September | 14.9 °C | 27.4 °C | 84.33 mm |
| October | 8.2 °C | 21.7 °C | 79.25 mm |
| November | 2.2 °C | 15.2 °C | 103.63 mm |
| December | -0.6 °C | 10.1 °C | 130.3 mm |
| Annual | 8.2 °C | 20.4 °C | 1296.92 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |