Grant, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.1 °C (low) to 23.8 °C (high). Annual precipitation averages 1198.1 Millimeters. Grant is located in USDA Plant Hardiness Zone 8a. 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 | -0.3 °C | 12.1 °C | 77.47 mm |
| February | 1.8 °C | 14.7 °C | 81.28 mm |
| March | 6.1 °C | 19 °C | 111.51 mm |
| April | 10.3 °C | 23.5 °C | 107.19 mm |
| May | 15.7 °C | 27.4 °C | 141.73 mm |
| June | 20.4 °C | 31.8 °C | 107.19 mm |
| July | 22.1 °C | 34.4 °C | 79.76 mm |
| August | 21.4 °C | 34.7 °C | 72.14 mm |
| September | 17.5 °C | 31.2 °C | 101.6 mm |
| October | 11.1 °C | 25.2 °C | 116.59 mm |
| November | 5.5 °C | 18.4 °C | 97.79 mm |
| December | 1.1 °C | 13.2 °C | 103.89 mm |
| Annual | 11.1 °C | 23.8 °C | 1198.14 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 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |