Robert Lee, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.1 °C (low) to 26.1 °C (high). Annual precipitation averages 539.8 Millimeters. Robert Lee is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -0.2 °C | 15.2 °C | 23.62 mm |
| February | 1.9 °C | 17.7 °C | 30.73 mm |
| March | 6.2 °C | 21.8 °C | 37.08 mm |
| April | 10.3 °C | 27 °C | 36.07 mm |
| May | 15.9 °C | 31 °C | 67.82 mm |
| June | 20.4 °C | 34.4 °C | 64.52 mm |
| July | 22 °C | 36.1 °C | 38.35 mm |
| August | 21.7 °C | 35.6 °C | 60.71 mm |
| September | 17.6 °C | 31.5 °C | 62.48 mm |
| October | 11.4 °C | 26.5 °C | 56.9 mm |
| November | 5.1 °C | 20.3 °C | 39.12 mm |
| December | 0.6 °C | 15.9 °C | 22.35 mm |
| Annual | 11.1 °C | 26.1 °C | 539.75 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |