December in Indianapolis averages a daily high of 5.1°C with nights around -3°C. Expect roughly 12.2 wet days totalling 78.9mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Indianapolis is September–October.
Based on INDIANAPOLIS INTERNATIONAL AIRPORT, IN US (12.5km), 1995–2024. 30 years of December data.