Mill Creek, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.9 °C (low) to 22.8 °C (high). Annual precipitation averages 1036.3 Millimeters. Mill Creek 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 °C | 11 °C | 50.8 mm |
| February | -0.1 °C | 13.3 °C | 56.9 mm |
| March | 4.8 °C | 18.1 °C | 81.03 mm |
| April | 9.2 °C | 22.6 °C | 94.74 mm |
| May | 14.6 °C | 26.3 °C | 142.75 mm |
| June | 19.6 °C | 30.9 °C | 117.09 mm |
| July | 21.6 °C | 34 °C | 80.01 mm |
| August | 21 °C | 34.3 °C | 70.36 mm |
| September | 16.8 °C | 30.1 °C | 104.39 mm |
| October | 10.3 °C | 23.9 °C | 104.39 mm |
| November | 4.2 °C | 17.6 °C | 66.8 mm |
| December | -0.7 °C | 12 °C | 67.06 mm |
| Annual | 9.9 °C | 22.8 °C | 1036.32 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 7b : -15°C to -12.2°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |