Cyril, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.5 °C (low) to 22.7 °C (high). Annual precipitation averages 833.4 Millimeters. Cyril 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 | -2.5 °C | 10.7 °C | 29.97 mm |
| February | -0.7 °C | 12.6 °C | 38.1 mm |
| March | 3.9 °C | 17.8 °C | 59.69 mm |
| April | 8.5 °C | 22.2 °C | 86.36 mm |
| May | 14.3 °C | 26.8 °C | 117.09 mm |
| June | 19.4 °C | 31.6 °C | 107.7 mm |
| July | 21.5 °C | 34.6 °C | 69.34 mm |
| August | 20.9 °C | 34.5 °C | 72.9 mm |
| September | 16.7 °C | 30.1 °C | 84.84 mm |
| October | 9.9 °C | 23.6 °C | 81.53 mm |
| November | 3.7 °C | 17 °C | 44.45 mm |
| December | -1.4 °C | 11.1 °C | 41.4 mm |
| Annual | 9.5 °C | 22.7 °C | 833.37 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |