Hanna, Oklahoma has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10 °C (low) to 22.8 °C (high). Annual precipitation averages 1151.6 Millimeters. Hanna 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 | -2.2 °C | 10.4 °C | 56.64 mm |
| February | -0.1 °C | 12.8 °C | 56.13 mm |
| March | 4.8 °C | 18.1 °C | 82.8 mm |
| April | 9.3 °C | 22.8 °C | 107.7 mm |
| May | 14.9 °C | 26.5 °C | 150.62 mm |
| June | 19.9 °C | 31.2 °C | 125.98 mm |
| July | 21.6 °C | 33.9 °C | 106.93 mm |
| August | 21.1 °C | 34 °C | 89.92 mm |
| September | 16.4 °C | 30.1 °C | 112.78 mm |
| October | 10.2 °C | 24.2 °C | 102.36 mm |
| November | 4.3 °C | 17.3 °C | 86.61 mm |
| December | -0.5 °C | 11.7 °C | 73.15 mm |
| Annual | 10 °C | 22.8 °C | 1151.62 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 | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |