January in Fountain Valley averages a daily high of 19.9°C with nights around 9.1°C. Expect roughly 5.8 wet days totalling 48.8mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Fountain Valley is April–November.
Based on SANTA ANA JOHN WAYNE AIRPORT, CA US (8.6km), 1995–2024. 25 years of January data.