Southmayd, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.5 °C (low) to 23.5 °C (high). Annual precipitation averages 1059.7 Millimeters. Southmayd is located in USDA Plant Hardiness Zone 8a. 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 | -0.2 °C | 11.8 °C | 57.91 mm |
| February | 1.8 °C | 14.3 °C | 67.31 mm |
| March | 6.1 °C | 18.6 °C | 95.25 mm |
| April | 10.6 °C | 23 °C | 91.95 mm |
| May | 15.9 °C | 27.1 °C | 134.87 mm |
| June | 20.7 °C | 31.8 °C | 106.93 mm |
| July | 22.9 °C | 34.6 °C | 69.6 mm |
| August | 22.4 °C | 34.7 °C | 68.83 mm |
| September | 18.2 °C | 30.6 °C | 91.19 mm |
| October | 11.9 °C | 24.8 °C | 112.78 mm |
| November | 5.9 °C | 18.2 °C | 81.03 mm |
| December | 1.2 °C | 12.8 °C | 82.04 mm |
| Annual | 11.5 °C | 23.5 °C | 1059.69 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 8a : -12.2°C to -9.4°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 |