Round Top, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 14.4 °C (low) to 26.3 °C (high). Annual precipitation averages 1048 Millimeters. Round Top is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 4.8 °C | 16.4 °C | 83.57 mm |
| February | 6.7 °C | 18.2 °C | 76.96 mm |
| March | 10.4 °C | 22.1 °C | 81.28 mm |
| April | 14 °C | 26.2 °C | 80.77 mm |
| May | 18.6 °C | 29.8 °C | 117.35 mm |
| June | 22.1 °C | 33.2 °C | 102.62 mm |
| July | 23.1 °C | 34.8 °C | 45.97 mm |
| August | 23.1 °C | 36 °C | 85.34 mm |
| September | 20.3 °C | 32.6 °C | 84.58 mm |
| October | 14.8 °C | 27.6 °C | 114.55 mm |
| November | 9.4 °C | 21.6 °C | 88.65 mm |
| December | 5.6 °C | 17.3 °C | 86.36 mm |
| Annual | 14.4 °C | 26.3 °C | 1048 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |