December in Shinagawa averages a daily high of 12.5°C. Expect roughly 9.3 wet days totalling 64.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Shinagawa is April–May.
Based on MATSUYAMA, JA (31.4km), 1995–2024. 23 years of December data.