May in San Rafael averages a daily high of 23.8°C with nights around 9.7°C. Expect roughly 3.4 wet days totalling 34mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit San Rafael is May–October.
Based on KENTFIELD, CA US (2.2km), 1995–2024. 24 years of May data.