Wynona, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.7 °C (low) to 21.7 °C (high). Annual precipitation averages 1028.2 Millimeters. Wynona 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 Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4 °C | 9.1 °C | 36.32 mm |
| February | -2.1 °C | 11.6 °C | 45.21 mm |
| March | 3 °C | 16.8 °C | 77.22 mm |
| April | 8.3 °C | 21.9 °C | 115.06 mm |
| May | 13.9 °C | 25.7 °C | 147.83 mm |
| June | 18.9 °C | 30.3 °C | 133.6 mm |
| July | 21.2 °C | 33.3 °C | 103.63 mm |
| August | 20.3 °C | 33.3 °C | 90.93 mm |
| September | 15.8 °C | 29.2 °C | 89.15 mm |
| October | 8.9 °C | 22.9 °C | 86.36 mm |
| November | 2.9 °C | 16.4 °C | 58.17 mm |
| December | -2.3 °C | 10 °C | 44.7 mm |
| Annual | 8.7 °C | 21.7 °C | 1028.18 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 |