Jefferson, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.9 °C (low) to 21.9 °C (high). Annual precipitation averages 855.5 Millimeters. Jefferson is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.9 °C | 8.5 °C | 26.67 mm |
| February | -3.1 °C | 10.9 °C | 32.51 mm |
| March | 1.8 °C | 16.3 °C | 62.74 mm |
| April | 6.7 °C | 21.6 °C | 88.39 mm |
| May | 12.9 °C | 26.5 °C | 109.47 mm |
| June | 18.6 °C | 32.2 °C | 119.38 mm |
| July | 21.1 °C | 34.9 °C | 91.69 mm |
| August | 20.1 °C | 34.1 °C | 94.23 mm |
| September | 15.5 °C | 30.1 °C | 65.28 mm |
| October | 8.3 °C | 23.1 °C | 83.57 mm |
| November | 1.7 °C | 15.8 °C | 44.2 mm |
| December | -3.5 °C | 9.3 °C | 37.34 mm |
| Annual | 7.9 °C | 21.9 °C | 855.47 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |