Grainola, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8 °C (low) to 20.7 °C (high). Annual precipitation averages 1006.4 Millimeters. Grainola is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.1 °C | 7.5 °C | 27.43 mm |
| February | -3.3 °C | 10 °C | 37.85 mm |
| March | 1.8 °C | 15.6 °C | 69.34 mm |
| April | 7.2 °C | 20.7 °C | 104.9 mm |
| May | 13.3 °C | 25.1 °C | 148.08 mm |
| June | 18.7 °C | 30.1 °C | 138.43 mm |
| July | 21 °C | 32.8 °C | 108.71 mm |
| August | 20 °C | 32.5 °C | 95 mm |
| September | 15.6 °C | 28.6 °C | 91.19 mm |
| October | 8.4 °C | 22.1 °C | 89.41 mm |
| November | 2.1 °C | 15.1 °C | 54.1 mm |
| December | -3.4 °C | 8.6 °C | 41.91 mm |
| Annual | 8 °C | 20.7 °C | 1006.35 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |