December in Fort Smith averages a daily high of 11.9°C with nights around 0.7°C. Expect roughly 7.7 wet days totalling 86.9mm. 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 December data.