Sulphur Springs, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.1 °C (low) to 24.3 °C (high). Annual precipitation averages 1158.5 Millimeters. Sulphur Springs 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 | 1.2 °C | 12.9 °C | 82.55 mm |
| February | 3.2 °C | 15.3 °C | 91.69 mm |
| March | 7.1 °C | 19.4 °C | 108.97 mm |
| April | 11.1 °C | 23.7 °C | 110.24 mm |
| May | 16.6 °C | 27.9 °C | 115.32 mm |
| June | 21.1 °C | 32.2 °C | 92.96 mm |
| July | 22.9 °C | 34.5 °C | 70.61 mm |
| August | 22.3 °C | 34.9 °C | 68.33 mm |
| September | 18.4 °C | 31.4 °C | 80.01 mm |
| October | 12.2 °C | 25.6 °C | 126.24 mm |
| November | 6.6 °C | 19.1 °C | 100.33 mm |
| December | 2.3 °C | 14.1 °C | 111.25 mm |
| Annual | 12.1 °C | 24.3 °C | 1158.5 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |