Petronila, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 17.2 °C (low) to 27.9 °C (high). Annual precipitation averages 761.5 Millimeters. Petronila is located in USDA Plant Hardiness Zone 9b.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 8.1 °C | 19.6 °C | 37.85 mm |
| February | 10.3 °C | 21.9 °C | 37.85 mm |
| March | 13.9 °C | 24.7 °C | 53.34 mm |
| April | 17.3 °C | 27.9 °C | 43.43 mm |
| May | 21.3 °C | 30.7 °C | 77.47 mm |
| June | 23.8 °C | 33.3 °C | 78.74 mm |
| July | 24.3 °C | 34.4 °C | 66.8 mm |
| August | 24.4 °C | 35.1 °C | 66.29 mm |
| September | 22.6 °C | 32.7 °C | 131.57 mm |
| October | 18.1 °C | 29.5 °C | 80.52 mm |
| November | 13 °C | 24.4 °C | 46.23 mm |
| December | 9.2 °C | 20.7 °C | 41.4 mm |
| Annual | 17.2 °C | 27.9 °C | 761.49 mm |
| Average First Frost Date | Frost Rare |
| Average Last Frost Date | |
| Average Days With Frost | Frost Rare |
| Plant Hardiness Zone | Zone 9b : -3.9°C to -1.1°C |
| Plant Hardiness Zone - 2012 | Zone 9b : -3.9°C to -1.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |