The best time to sell a house in Southern California depends on various factors such as location, market conditions, and weather. Generally, the real estate market is slower in winter and picks up in spring. In warmer areas like San Diego and Los Angeles, winter may be a good time to sell due to less competition. In colder areas like Sacramento and Fresno, spring may be better. It's recommended to consult with local real estate agents for the most up-to-date advice. Different counties have different optimal selling months, such as March, April, and May in Los Angeles County, and February or March in Orange County.