Stilwell, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9 °C (low) to 21 °C (high). Annual precipitation averages 1292.6 Millimeters. Stilwell 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 Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -2.7 °C | 8.8 °C | 74.42 mm |
| February | -0.9 °C | 11.2 °C | 65.53 mm |
| March | 3.7 °C | 16 °C | 107.7 mm |
| April | 8.2 °C | 21 °C | 127.51 mm |
| May | 13.4 °C | 24.8 °C | 161.04 mm |
| June | 18.3 °C | 29.3 °C | 135.38 mm |
| July | 20.6 °C | 32.2 °C | 106.17 mm |
| August | 19.8 °C | 32.2 °C | 90.93 mm |
| September | 15.6 °C | 28.3 °C | 124.21 mm |
| October | 9.2 °C | 22.2 °C | 114.3 mm |
| November | 3.7 °C | 15.7 °C | 102.62 mm |
| December | -1.1 °C | 10 °C | 82.8 mm |
| Annual | 9 °C | 21 °C | 1292.61 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 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 |