McLain, Mississippi has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.7 °C (low) to 25.9 °C (high). Annual precipitation averages 1611.9 Millimeters. McLain 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 | 2.2 °C | 16.2 °C | 158.75 mm |
| February | 3.8 °C | 18.4 °C | 135.64 mm |
| March | 7.3 °C | 22.2 °C | 147.83 mm |
| April | 10.8 °C | 26.1 °C | 128.02 mm |
| May | 15.6 °C | 30 °C | 120.4 mm |
| June | 19.7 °C | 32.7 °C | 154.43 mm |
| July | 21.1 °C | 33.7 °C | 162.81 mm |
| August | 21 °C | 33.7 °C | 141.48 mm |
| September | 18.1 °C | 31.9 °C | 117.86 mm |
| October | 11.6 °C | 27.2 °C | 87.63 mm |
| November | 5.7 °C | 21.3 °C | 109.22 mm |
| December | 3.1 °C | 17.2 °C | 147.83 mm |
| Annual | 11.7 °C | 25.9 °C | 1611.9 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |