Rosser, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.5 °C (low) to 24.8 °C (high). Annual precipitation averages 1044.2 Millimeters. Rosser is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.6 °C | 13.6 °C | 78.49 mm |
| February | 3.7 °C | 16.1 °C | 77.47 mm |
| March | 7.7 °C | 19.9 °C | 93.98 mm |
| April | 11.6 °C | 24.2 °C | 95.76 mm |
| May | 17.2 °C | 28.2 °C | 118.11 mm |
| June | 21.4 °C | 32.7 °C | 96.27 mm |
| July | 22.9 °C | 35 °C | 47.75 mm |
| August | 22.7 °C | 35.5 °C | 62.74 mm |
| September | 19 °C | 31.9 °C | 77.22 mm |
| October | 12.8 °C | 26.2 °C | 123.44 mm |
| November | 6.9 °C | 19.7 °C | 77.98 mm |
| December | 2.7 °C | 14.8 °C | 95 mm |
| Annual | 12.5 °C | 24.8 °C | 1044.21 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 30-40 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°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 |