Grayson Valley, Alabama has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.4 °C (low) to 22.1 °C (high). Annual precipitation averages 1472.2 Millimeters. Grayson Valley is located in USDA Plant Hardiness Zone 8a. 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 | 0.9 °C | 11.2 °C | 133.6 mm |
| February | 2.6 °C | 13.6 °C | 130.81 mm |
| March | 6.5 °C | 18.2 °C | 146.3 mm |
| April | 10.7 °C | 22.6 °C | 130.81 mm |
| May | 15.6 °C | 26.3 °C | 123.19 mm |
| June | 19.9 °C | 29.7 °C | 123.19 mm |
| July | 21.7 °C | 31.4 °C | 129.79 mm |
| August | 21.2 °C | 31.2 °C | 103.89 mm |
| September | 18.1 °C | 28.6 °C | 115.57 mm |
| October | 11.8 °C | 23.1 °C | 86.61 mm |
| November | 5.8 °C | 17.2 °C | 119.89 mm |
| December | 2.4 °C | 12.6 °C | 128.52 mm |
| Annual | 11.4 °C | 22.1 °C | 1472.17 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 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |