June in Napa averages a daily high of 27.9°C with nights around 12.1°C. Rain is rare — about 0.8 wet days and 3.9mm across the month. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Napa is April–October.
Based on NAPA STATE HOSPITAL, CA US (2.8km), 1995–2024. 30 years of June data.