October in Sunnyvale averages a daily high of 23.2°C with nights around 11.8°C. Expect roughly 4 wet days totalling 15.6mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Sunnyvale is May–October.
Based on MOFFETT FEDERAL AIRFIELD, CA US (4.2km), 1995–2024. 20 years of October data.