McCool, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.9 °C (low) to 23.4 °C (high). Annual precipitation averages 1470.7 Millimeters. McCool 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 | 0.7 °C | 12.5 °C | 132.33 mm |
| February | 2.2 °C | 15 °C | 135.64 mm |
| March | 6.1 °C | 19.5 °C | 141.22 mm |
| April | 10.3 °C | 23.8 °C | 150.62 mm |
| May | 15.3 °C | 27.7 °C | 118.87 mm |
| June | 19.4 °C | 31.2 °C | 110.49 mm |
| July | 21.2 °C | 32.6 °C | 125.48 mm |
| August | 20.7 °C | 32.4 °C | 110.49 mm |
| September | 17.2 °C | 29.9 °C | 97.54 mm |
| October | 10.8 °C | 24.6 °C | 95 mm |
| November | 4.9 °C | 18.3 °C | 113.28 mm |
| December | 2.1 °C | 13.7 °C | 139.7 mm |
| Annual | 10.9 °C | 23.4 °C | 1470.66 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 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |