Fort Smith, Arkansas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.1 °C (low) to 22.6 °C (high). Annual precipitation averages 1233.4 Millimeters. Fort Smith 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 | -1.8 °C | 10.3 °C | 81.03 mm |
| February | 0.2 °C | 12.8 °C | 71.63 mm |
| March | 4.6 °C | 17.6 °C | 109.73 mm |
| April | 9.3 °C | 22.7 °C | 123.19 mm |
| May | 15.1 °C | 26.6 °C | 145.8 mm |
| June | 19.9 °C | 31.2 °C | 111.51 mm |
| July | 21.9 °C | 33.9 °C | 91.69 mm |
| August | 21.2 °C | 33.8 °C | 95.5 mm |
| September | 16.9 °C | 29.9 °C | 101.35 mm |
| October | 10.1 °C | 23.9 °C | 104.39 mm |
| November | 4.1 °C | 17.3 °C | 103.38 mm |
| December | -0.2 °C | 11.5 °C | 94.23 mm |
| Annual | 10.1 °C | 22.6 °C | 1233.43 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 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |