January in Lake Forest averages a daily high of 21.1°C with nights around 8.6°C. Expect roughly 4.3 wet days totalling 63.9mm. Comfortable conditions for being outdoors all day.
Across the year, the best time to visit Lake Forest is October–June.
Based on IRVINE RANCH, CA US (8.7km), 1995–2024. 20 years of January data.