Decatur, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 52 °F (low) to 75.9 °F (high). Annual precipitation averages 58.8 Inches. Decatur is located in USDA Plant Hardiness Zone 8b. 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 | 34.4 °F | 56.9 °F | 5.8 in. |
| February | 37.4 °F | 61.5 °F | 5.22 in. |
| March | 43.9 °F | 69.0 °F | 5.73 in. |
| April | 50.7 °F | 76.1 °F | 6.15 in. |
| May | 59.4 °F | 83.1 °F | 4.21 in. |
| June | 67.0 °F | 89.8 °F | 4.54 in. |
| July | 69.8 °F | 91.6 °F | 5.04 in. |
| August | 68.8 °F | 91.4 °F | 4.82 in. |
| September | 63.3 °F | 87.5 °F | 3.55 in. |
| October | 51.3 °F | 78.1 °F | 3.66 in. |
| November | 40.9 °F | 67.1 °F | 4.7 in. |
| December | 36.5 °F | 59.2 °F | 5.42 in. |
| Annual | 52 °F | 75.9 °F | 58.84 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |