Grainola, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 46.4 °F (low) to 69.3 °F (high). Annual precipitation averages 39.6 Inches. 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 | 22.9 °F | 45.5 °F | 1.08 in. |
| February | 26.0 °F | 50.0 °F | 1.49 in. |
| March | 35.2 °F | 60.0 °F | 2.73 in. |
| April | 44.9 °F | 69.2 °F | 4.13 in. |
| May | 55.9 °F | 77.1 °F | 5.83 in. |
| June | 65.6 °F | 86.1 °F | 5.45 in. |
| July | 69.8 °F | 91.1 °F | 4.28 in. |
| August | 68.0 °F | 90.5 °F | 3.74 in. |
| September | 60.0 °F | 83.5 °F | 3.59 in. |
| October | 47.2 °F | 71.7 °F | 3.52 in. |
| November | 35.8 °F | 59.2 °F | 2.13 in. |
| December | 25.8 °F | 47.4 °F | 1.65 in. |
| Annual | 46.4 °F | 69.3 °F | 39.62 in. |
| 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 : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |