Walnut, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.6 °C (low) to 21.9 °C (high). Annual precipitation averages 1455.9 Millimeters. Walnut 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 | -1.2 °C | 9.8 °C | 120.14 mm |
| February | 0.4 °C | 12.4 °C | 127.76 mm |
| March | 4.4 °C | 17.2 °C | 141.22 mm |
| April | 9.1 °C | 22.4 °C | 144.02 mm |
| May | 14.5 °C | 26.6 °C | 134.87 mm |
| June | 18.8 °C | 30.4 °C | 116.59 mm |
| July | 20.7 °C | 32.1 °C | 115.82 mm |
| August | 19.8 °C | 32 °C | 92.71 mm |
| September | 15.9 °C | 29.1 °C | 102.62 mm |
| October | 9.2 °C | 23.2 °C | 101.6 mm |
| November | 3.7 °C | 16.7 °C | 108.97 mm |
| December | 0.4 °C | 11.3 °C | 149.61 mm |
| Annual | 9.6 °C | 21.9 °C | 1455.93 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |