January in Ansan-si averages a daily high of 2.1°C with nights around -5.4°C. Expect roughly 4.6 wet days totalling 14.2mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Ansan-si is May–June.
Based on INCHEON, KS (23.1km), 1995–2024. 19 years of January data.