December in Katori-shi averages a daily high of 12.5°C with nights around 5.4°C. Expect roughly 8.1 wet days totalling 90.4mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Katori-shi is May–October.
Based on CHOSHI, JA (36.5km), 1995–2024. 19 years of December data.