January in Tustin averages a daily high of 21.2°C with nights around 9.1°C. Expect roughly 6.2 wet days totalling 68.4mm. 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 January data.