December in Knoxville averages a daily high of 10.7°C with nights around -0.9°C. Expect roughly 10.7 wet days totalling 146.1mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit Knoxville is April–May.
Based on KNOXVILLE EXPERIMENTAL STATION, TN US (7.7km), 1995–2024. 29 years of December data.