Port Lavaca, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 62.2 °F (low) to 79 °F (high). Annual precipitation averages 43.2 Inches. Port Lavaca is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 44.7 °F | 64.1 °F | 3.04 in. |
| February | 48.9 °F | 67.0 °F | 2.11 in. |
| March | 55.6 °F | 72.1 °F | 2.96 in. |
| April | 61.7 °F | 78.0 °F | 2.82 in. |
| May | 69.5 °F | 84.1 °F | 4.2 in. |
| June | 75.0 °F | 89.2 °F | 5.07 in. |
| July | 76.5 °F | 91.4 °F | 3.73 in. |
| August | 76.2 °F | 92.4 °F | 3.12 in. |
| September | 72.1 °F | 88.8 °F | 5.45 in. |
| October | 64.0 °F | 82.3 °F | 4.54 in. |
| November | 54.4 °F | 72.7 °F | 3.35 in. |
| December | 47.3 °F | 65.7 °F | 2.83 in. |
| Annual | 62.2 °F | 79 °F | 43.22 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 |