Robstown, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 62.8 °F (low) to 82.1 °F (high). Annual precipitation averages 30.1 Inches. Robstown is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 46.3 °F | 67.0 °F | 1.47 in. |
| February | 50.4 °F | 71.3 °F | 1.47 in. |
| March | 56.8 °F | 76.4 °F | 2.11 in. |
| April | 63.0 °F | 82.1 °F | 1.7 in. |
| May | 70.1 °F | 87.1 °F | 3.0 in. |
| June | 74.6 °F | 92.0 °F | 3.09 in. |
| July | 75.7 °F | 93.9 °F | 2.62 in. |
| August | 75.8 °F | 95.1 °F | 2.71 in. |
| September | 72.5 °F | 90.8 °F | 5.12 in. |
| October | 64.4 °F | 85.0 °F | 3.21 in. |
| November | 55.3 °F | 75.8 °F | 1.91 in. |
| December | 48.4 °F | 69.0 °F | 1.66 in. |
| Annual | 62.8 °F | 82.1 °F | 30.07 in. |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : 25°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 9b : 25°F to 20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |