Grayson, Louisiana has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12 °C (low) to 24.9 °C (high). Annual precipitation averages 1488.4 Millimeters. Grayson is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 2.1 °C | 14.4 °C | 146.81 mm |
| February | 3.6 °C | 16.7 °C | 129.54 mm |
| March | 7.4 °C | 21.2 °C | 136.65 mm |
| April | 11.4 °C | 24.9 °C | 153.16 mm |
| May | 16.4 °C | 29 °C | 123.7 mm |
| June | 20.3 °C | 32.2 °C | 118.11 mm |
| July | 21.8 °C | 33.7 °C | 111.25 mm |
| August | 21.3 °C | 34.1 °C | 93.47 mm |
| September | 18.1 °C | 31.4 °C | 93.98 mm |
| October | 11.7 °C | 26.2 °C | 110.24 mm |
| November | 6.3 °C | 20 °C | 127.76 mm |
| December | 3 °C | 15.4 °C | 143.76 mm |
| Annual | 12 °C | 24.9 °C | 1488.43 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |