Round Mountain, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 55.1 °F (low) to 77.4 °F (high). Annual precipitation averages 31.3 Inches. Round Mountain is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 37.2 °F | 59.8 °F | 1.98 in. |
| February | 40.7 °F | 63.3 °F | 1.92 in. |
| March | 47.5 °F | 70.3 °F | 2.49 in. |
| April | 54.3 °F | 77.3 °F | 2.33 in. |
| May | 62.9 °F | 83.3 °F | 4.14 in. |
| June | 69.1 °F | 89.8 °F | 2.85 in. |
| July | 71.3 °F | 93.2 °F | 2.07 in. |
| August | 71.3 °F | 94.6 °F | 1.82 in. |
| September | 65.6 °F | 88.0 °F | 3.42 in. |
| October | 56.1 °F | 79.6 °F | 3.39 in. |
| November | 46.4 °F | 68.7 °F | 2.81 in. |
| December | 38.3 °F | 60.9 °F | 2.03 in. |
| Annual | 55.1 °F | 77.4 °F | 31.25 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8b : 15°F to 20°F |
| Plant Hardiness Zone - 2012 | Zone 8b : 15°F to 20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |