Harrold, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.3 °C (low) to 24.3 °C (high). Annual precipitation averages 734.8 Millimeters. Harrold 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. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.8 °C | 12.1 °C | 31.75 mm |
| February | -0.1 °C | 14.4 °C | 37.59 mm |
| March | 4.5 °C | 19.2 °C | 54.61 mm |
| April | 8.9 °C | 24 °C | 66.55 mm |
| May | 15.1 °C | 28.8 °C | 105.41 mm |
| June | 20.3 °C | 33.6 °C | 87.88 mm |
| July | 22.4 °C | 36.1 °C | 59.18 mm |
| August | 21.9 °C | 36 °C | 60.96 mm |
| September | 17.6 °C | 31.4 °C | 70.36 mm |
| October | 10.8 °C | 25.4 °C | 74.17 mm |
| November | 4.3 °C | 18.3 °C | 46.99 mm |
| December | -0.8 °C | 12.8 °C | 39.37 mm |
| Annual | 10.3 °C | 24.3 °C | 734.82 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| 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 7b : -15°C to -12.2°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |