Blackwell, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 50.8 °F (low) to 77.2 °F (high). Annual precipitation averages 21.8 Inches. Blackwell 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. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 30.5 °F | 57.7 °F | 0.84 in. |
| February | 34.3 °F | 61.8 °F | 1.22 in. |
| March | 42.0 °F | 69.8 °F | 1.44 in. |
| April | 49.3 °F | 78.1 °F | 1.58 in. |
| May | 59.5 °F | 85.6 °F | 2.45 in. |
| June | 67.9 °F | 91.8 °F | 2.85 in. |
| July | 69.7 °F | 94.9 °F | 1.37 in. |
| August | 69.4 °F | 94.7 °F | 2.54 in. |
| September | 62.8 °F | 87.9 °F | 2.5 in. |
| October | 51.4 °F | 78.5 °F | 2.67 in. |
| November | 40.0 °F | 66.9 °F | 1.42 in. |
| December | 32.2 °F | 58.8 °F | 0.89 in. |
| Annual | 50.8 °F | 77.2 °F | 21.77 in. |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 8a : 10°F to 15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |