Grimsley, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.4 °C (low) to 18.8 °C (high). Annual precipitation averages 1494.5 Millimeters. Grimsley is located in USDA Plant Hardiness Zone 7a. 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 | -3.7 °C | 6.6 °C | 122.17 mm |
| February | -1.8 °C | 9.2 °C | 127.51 mm |
| March | 1.8 °C | 13.8 °C | 141.48 mm |
| April | 6.7 °C | 19.4 °C | 139.45 mm |
| May | 11.9 °C | 23.7 °C | 128.52 mm |
| June | 16.1 °C | 27.2 °C | 132.33 mm |
| July | 18.2 °C | 28.8 °C | 144.53 mm |
| August | 17.5 °C | 28.6 °C | 112.27 mm |
| September | 14 °C | 25.9 °C | 104.39 mm |
| October | 7.5 °C | 20.4 °C | 82.3 mm |
| November | 2 °C | 13.6 °C | 105.66 mm |
| December | -1.3 °C | 8.5 °C | 153.92 mm |
| Annual | 7.4 °C | 18.8 °C | 1494.53 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 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |