weather in california during january
January has the coolest weather of the year for most of the California coast, yet Avila Beach, Long Beach and Laguna Beach usually manage to reach highs of at least 67 degrees Fahrenheit (19 degrees Celsius). Along the Pacific Ocean in northern California, the days in January usually warm up to the mid-50s Fahrenheit.
There is a possibility of rain in January, because it's in the rainy season typical of a Mediterranean climate. It doesn't rain every day; it depends on what storm systems move into California from the north. If it rains, temperatures will probably be in the 50s F while it's raining.