December in San Rafael averages a daily high of 14.1°C with nights around 5.7°C. Expect roughly 11.9 wet days totalling 268mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit San Rafael is May–October.
Based on KENTFIELD, CA US (2.2km), 1995–2024. 28 years of December data.