Harrisburg, Arkansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 51 °F (low) to 70.5 °F (high). Annual precipitation averages 51.3 Inches. Harrisburg 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 | 30.2 °F | 47.0 °F | 3.81 in. |
| February | 33.3 °F | 51.7 °F | 4.12 in. |
| March | 41.2 °F | 60.7 °F | 4.92 in. |
| April | 50.3 °F | 71.4 °F | 5.62 in. |
| May | 60.2 °F | 79.9 °F | 5.19 in. |
| June | 68.4 °F | 87.9 °F | 3.98 in. |
| July | 71.5 °F | 90.3 °F | 3.93 in. |
| August | 69.7 °F | 89.5 °F | 3.05 in. |
| September | 62.3 °F | 84.2 °F | 3.02 in. |
| October | 50.7 °F | 73.6 °F | 4.29 in. |
| November | 41.0 °F | 60.1 °F | 4.36 in. |
| December | 33.3 °F | 49.9 °F | 4.98 in. |
| Annual | 51 °F | 70.5 °F | 51.27 in. |
| 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 : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |