Hillsboro, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.8 °C (low) to 25.2 °C (high). Annual precipitation averages 982.2 Millimeters. Hillsboro 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 | 1.9 °C | 14.3 °C | 70.1 mm |
| February | 4 °C | 16.6 °C | 70.1 mm |
| March | 8.1 °C | 20.4 °C | 90.93 mm |
| April | 12.1 °C | 24.6 °C | 90.68 mm |
| May | 17.3 °C | 28.7 °C | 115.57 mm |
| June | 21.4 °C | 32.9 °C | 98.55 mm |
| July | 23.2 °C | 35.3 °C | 43.43 mm |
| August | 23.1 °C | 35.7 °C | 58.42 mm |
| September | 19.3 °C | 32.2 °C | 78.23 mm |
| October | 13.2 °C | 26.6 °C | 118.87 mm |
| November | 7.5 °C | 19.9 °C | 71.37 mm |
| December | 3 °C | 15.2 °C | 75.95 mm |
| Annual | 12.8 °C | 25.2 °C | 982.2 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 30-40 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 |