Stillwater, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 47.5 °F (low) to 71.7 °F (high). Annual precipitation averages 36 Inches. Stillwater 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 | 24.8 °F | 49.0 °F | 1.31 in. |
| February | 28.2 °F | 52.6 °F | 1.48 in. |
| March | 36.6 °F | 62.3 °F | 2.66 in. |
| April | 45.8 °F | 71.4 °F | 3.95 in. |
| May | 56.8 °F | 79.3 °F | 4.84 in. |
| June | 66.6 °F | 88.0 °F | 4.65 in. |
| July | 70.8 °F | 93.3 °F | 3.43 in. |
| August | 69.1 °F | 93.1 °F | 3.27 in. |
| September | 60.5 °F | 85.5 °F | 3.33 in. |
| October | 47.9 °F | 73.8 °F | 3.27 in. |
| November | 36.4 °F | 61.6 °F | 2.12 in. |
| December | 26.9 °F | 50.2 °F | 1.67 in. |
| Annual | 47.5 °F | 71.7 °F | 35.98 in. |
| 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 : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |