Greenfield, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.7 °C (low) to 21.9 °C (high). Annual precipitation averages 791.7 Millimeters. Greenfield 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 | -3.6 °C | 9.4 °C | 25.91 mm |
| February | -2 °C | 11.4 °C | 31.24 mm |
| March | 2.7 °C | 16.7 °C | 58.17 mm |
| April | 7.5 °C | 21.7 °C | 75.95 mm |
| May | 13.6 °C | 26.3 °C | 111 mm |
| June | 18.9 °C | 31.4 °C | 103.63 mm |
| July | 21.3 °C | 34.4 °C | 64.01 mm |
| August | 20.4 °C | 33.8 °C | 95.25 mm |
| September | 16 °C | 29.4 °C | 71.88 mm |
| October | 9.2 °C | 22.9 °C | 74.93 mm |
| November | 2.6 °C | 15.9 °C | 43.43 mm |
| December | -2.5 °C | 9.9 °C | 36.32 mm |
| Annual | 8.7 °C | 21.9 °C | 791.72 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 | Extreme Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |