Winchester, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.9 °C (low) to 22.1 °C (high). Annual precipitation averages 1064.5 Millimeters. Winchester is located in USDA Plant Hardiness Zone 7b. 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 | -2.2 °C | 9.9 °C | 44.45 mm |
| February | -0.5 °C | 12.1 °C | 51.56 mm |
| March | 4.6 °C | 17.1 °C | 81.28 mm |
| April | 9.2 °C | 21.9 °C | 111.51 mm |
| May | 14.8 °C | 25.8 °C | 150.11 mm |
| June | 19.7 °C | 30.4 °C | 112.78 mm |
| July | 21.9 °C | 33.7 °C | 96.52 mm |
| August | 21.1 °C | 33.7 °C | 91.44 mm |
| September | 16.8 °C | 29.6 °C | 92.96 mm |
| October | 10.1 °C | 23.4 °C | 101.09 mm |
| November | 4.4 °C | 17.1 °C | 72.9 mm |
| December | -0.7 °C | 10.9 °C | 57.91 mm |
| Annual | 9.9 °C | 22.1 °C | 1064.51 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |