Harrell, Arkansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.7 °C (low) to 23.6 °C (high). Annual precipitation averages 1411.2 Millimeters. Harrell 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 °C | 12.2 °C | 119.63 mm |
| February | 1.7 °C | 14.6 °C | 120.4 mm |
| March | 5.6 °C | 19.3 °C | 141.73 mm |
| April | 10.2 °C | 24 °C | 147.07 mm |
| May | 15.5 °C | 27.7 °C | 127.51 mm |
| June | 19.8 °C | 31.6 °C | 100.08 mm |
| July | 21.6 °C | 33.4 °C | 97.54 mm |
| August | 20.7 °C | 33.4 °C | 93.73 mm |
| September | 17.1 °C | 30.5 °C | 91.69 mm |
| October | 10.2 °C | 24.7 °C | 117.09 mm |
| November | 4.7 °C | 18.2 °C | 109.22 mm |
| December | 1.4 °C | 13.4 °C | 145.54 mm |
| Annual | 10.7 °C | 23.6 °C | 1411.23 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |