Living in Southern California, you can pretty much expect two seasons: cold/rainy and hot/windy. Pack all of the typical clothes, but leave any earmuffs, gloves, and any other heavy-duty snow gear at home. During winter, the typical student wears jeans, a shirt, and a jacket (beanies and scarves are optional). The summer is what you really have to watch out for because summer days get super hot, and all you need to wear is shorts, a tank top, flip-flops, and sunglasses. Luckily, the dorms have central air conditioning. Most students head out to the beach when this weather hits. Good places to check out are Venice Beach, Ocean Park, Malibu, and Dockweiler Beach (the only beach with bonfire pits). A good rule of thumb for weather is that when it is overcast inland, it will be a clear day at the beach.
But watch out for "June gloom," which causes overcast days. In the fall, you can expect to experience the warm, strong Santa Ana winds (allergies can really pick up at this time). Don't be surprised if you hear about the chaparral fires, which periodically sweep through the San Fernando Valley. Another common term you might hear is "earthquake weather," which is characterized by sporadic, extreme shifts in weather from hot to cold. Although some people believe this type of weather will cause earthquakes, there is no actual proof that it does. Earthquakes, however, are a common occurrence. You might feel one or two earthquakes a year, and they will most likely be little ones, what some people call "shake and bakes," but there isn't anything to worry about. Just remember that door openings are the safest places to stand, and hope that your computer is in a safe place.