December in Ames averages a daily high of 1.5°C with nights around -8.3°C. Expect roughly 5.9 wet days totalling 30mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Ames is September.
Based on AMES MUNICIPAL AIRPORT, IA US (4.9km), 1995–2024. 29 years of December data.