January in Saint Charles averages a daily high of 4.2°C with nights around -5.6°C. Expect roughly 7.3 wet days totalling 69.4mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Saint Charles is September–October.
Based on ST CHARLES ELM POINT, MO US (4.4km), 1995–2024. 29 years of January data.