Jefferson, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.7 °C (low) to 24.6 °C (high). Annual precipitation averages 1284.5 Millimeters. Jefferson 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 | 1.2 °C | 13.8 °C | 105.92 mm |
| February | 3.1 °C | 16.2 °C | 105.66 mm |
| March | 7 °C | 20.5 °C | 126.24 mm |
| April | 11 °C | 24.7 °C | 115.06 mm |
| May | 16.3 °C | 28.5 °C | 121.67 mm |
| June | 20.7 °C | 32.2 °C | 121.41 mm |
| July | 22.4 °C | 34.2 °C | 75.95 mm |
| August | 21.7 °C | 34.6 °C | 69.34 mm |
| September | 17.8 °C | 31.3 °C | 99.82 mm |
| October | 11.2 °C | 25.7 °C | 118.11 mm |
| November | 5.9 °C | 19.2 °C | 100.58 mm |
| December | 2.3 °C | 14.6 °C | 124.71 mm |
| Annual | 11.7 °C | 24.6 °C | 1284.47 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |