December in Pleasanton averages a daily high of 14.6°C with nights around 3.5°C. Expect roughly 10.1 wet days totalling 75.8mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Pleasanton is April–June.
Based on LIVERMORE MUNICIPAL AIRPORT, CA US (6.3km), 1995–2024. 27 years of December data.