September in Fort Smith averages a daily high of 30.5°C with nights around 17.8°C. Expect roughly 6.7 wet days totalling 93.5mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Fort Smith is April–May.
Based on FORT SMITH REGIONAL AIRPORT, AR US (6.6km), 1995–2024. 30 years of September data.