May in Santa Rosa averages a daily high of 23.3°C with nights around 9°C. Expect roughly 4.8 wet days totalling 40mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Santa Rosa is May–October.
Based on SANTA ROSA, CA US (1.7km), 1995–2024. 19 years of May data.