O'Kean, Arkansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.7 °C (low) to 20.8 °C (high). Annual precipitation averages 1276.9 Millimeters. O'Kean is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.1 °C | 7.4 °C | 95.76 mm |
| February | -0.3 °C | 10.3 °C | 99.06 mm |
| March | 4.1 °C | 15.5 °C | 120.9 mm |
| April | 9.3 °C | 21.2 °C | 136.4 mm |
| May | 15.1 °C | 26.1 °C | 130.05 mm |
| June | 19.7 °C | 30.7 °C | 85.09 mm |
| July | 21.6 °C | 32.1 °C | 94.74 mm |
| August | 20.3 °C | 31.4 °C | 91.44 mm |
| September | 15.9 °C | 28.2 °C | 89.92 mm |
| October | 9.2 °C | 22.6 °C | 97.28 mm |
| November | 3.8 °C | 15.1 °C | 119.63 mm |
| December | -0.4 °C | 8.9 °C | 116.59 mm |
| Annual | 9.7 °C | 20.8 °C | 1276.86 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 75-100 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |