Harrison, Arkansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.3 °C (low) to 20.8 °C (high). Annual precipitation averages 1198.6 Millimeters. Harrison is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.1 °C | 8.3 °C | 76.96 mm |
| February | -1.4 °C | 10.9 °C | 72.14 mm |
| March | 2.8 °C | 15.7 °C | 114.3 mm |
| April | 7.8 °C | 21 °C | 135.64 mm |
| May | 13.2 °C | 25.2 °C | 133.6 mm |
| June | 17.7 °C | 29.7 °C | 97.79 mm |
| July | 19.7 °C | 32.1 °C | 94.49 mm |
| August | 18.9 °C | 31.7 °C | 83.31 mm |
| September | 14.7 °C | 28.1 °C | 106.68 mm |
| October | 8.4 °C | 22.1 °C | 99.31 mm |
| November | 2.9 °C | 15.3 °C | 101.09 mm |
| December | -1.5 °C | 9.7 °C | 83.31 mm |
| Annual | 8.3 °C | 20.8 °C | 1198.62 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |