May in Tustin averages a daily high of 24.2°C with nights around 14.2°C. Rain is rare — about 1.9 wet days and 7.9mm across the month. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Tustin is April–July.
Based on SANTA ANA FIRE STATION, CA US (3.8km), 1995–2024. 30 years of May data.