Round Rock, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 56.2 °F (low) to 79.1 °F (high). Annual precipitation averages 37.2 Inches. Round Rock 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 | 37.8 °F | 61.3 °F | 2.63 in. |
| February | 41.4 °F | 64.7 °F | 2.1 in. |
| March | 48.3 °F | 71.6 °F | 3.03 in. |
| April | 55.3 °F | 78.8 °F | 2.65 in. |
| May | 64.4 °F | 85.3 °F | 4.51 in. |
| June | 71.0 °F | 91.7 °F | 3.6 in. |
| July | 73.1 °F | 94.9 °F | 2.67 in. |
| August | 72.7 °F | 96.0 °F | 2.43 in. |
| September | 67.5 °F | 90.2 °F | 3.44 in. |
| October | 57.3 °F | 81.6 °F | 4.26 in. |
| November | 46.8 °F | 70.3 °F | 3.11 in. |
| December | 39.3 °F | 62.4 °F | 2.78 in. |
| Annual | 56.2 °F | 79.1 °F | 37.21 in. |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Feb. 21 - Feb. 29 |
| Average Days With Frost | 10-20 Days |
| Plant Hardiness Zone | Zone 9a : 20°F to 25°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |