Rockdale, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.6 °C (low) to 26.1 °C (high). Annual precipitation averages 940.8 Millimeters. Rockdale is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Feb. 21 - Feb. 29 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.4 °C | 15.9 °C | 76.96 mm |
| February | 5.6 °C | 17.9 °C | 62.48 mm |
| March | 9.1 °C | 21.9 °C | 77.72 mm |
| April | 13 °C | 25.8 °C | 63.5 mm |
| May | 18 °C | 29.6 °C | 121.16 mm |
| June | 21.8 °C | 33.2 °C | 81.28 mm |
| July | 22.9 °C | 35.1 °C | 52.07 mm |
| August | 22.7 °C | 35.8 °C | 69.85 mm |
| September | 19.6 °C | 32.4 °C | 68.58 mm |
| October | 13.9 °C | 27.4 °C | 101.35 mm |
| November | 8.4 °C | 21.2 °C | 83.82 mm |
| December | 4.4 °C | 16.7 °C | 82.04 mm |
| Annual | 13.6 °C | 26.1 °C | 940.81 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |