Watertown, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.4 °C (low) to 21.1 °C (high). Annual precipitation averages 1430.3 Millimeters. Watertown is located in USDA Plant Hardiness Zone 7b. 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 | -2.4 °C | 8.6 °C | 124.21 mm |
| February | -0.9 °C | 11.1 °C | 127.25 mm |
| March | 2.9 °C | 15.9 °C | 133.35 mm |
| April | 7.6 °C | 21.4 °C | 121.92 mm |
| May | 12.9 °C | 25.9 °C | 127 mm |
| June | 17.6 °C | 29.9 °C | 124.46 mm |
| July | 19.8 °C | 31.7 °C | 139.7 mm |
| August | 18.8 °C | 31.3 °C | 98.55 mm |
| September | 14.8 °C | 28.4 °C | 100.84 mm |
| October | 8.1 °C | 22.5 °C | 89.92 mm |
| November | 2.3 °C | 15.7 °C | 95 mm |
| December | -0.6 °C | 10.3 °C | 148.08 mm |
| Annual | 8.4 °C | 21.1 °C | 1430.28 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 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 |