Roby, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 51.1 °F (low) to 77.2 °F (high). Annual precipitation averages 23.5 Inches. Roby 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 | 30.7 °F | 56.9 °F | 1.1 in. |
| February | 34.0 °F | 61.0 °F | 1.18 in. |
| March | 41.6 °F | 69.5 °F | 1.72 in. |
| April | 49.5 °F | 78.5 °F | 1.68 in. |
| May | 59.7 °F | 85.7 °F | 3.09 in. |
| June | 68.1 °F | 92.6 °F | 3.27 in. |
| July | 71.4 °F | 96.1 °F | 1.61 in. |
| August | 70.4 °F | 95.4 °F | 2.37 in. |
| September | 63.0 °F | 87.5 °F | 2.86 in. |
| October | 51.9 °F | 78.6 °F | 2.11 in. |
| November | 40.4 °F | 66.5 °F | 1.25 in. |
| December | 32.4 °F | 57.8 °F | 1.25 in. |
| Annual | 51.1 °F | 77.2 °F | 23.49 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 7b : 5°F to 10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |