It's California season changes doesn't appear very much on environment. But in winter there will be worse weather, more raining, in some places raining with a little snow (but not too much snow, it won't appear on roads or trees etc.) and also in winter there will be ice, witch is very dangerous
of course there will be temperature changes, but I don't think main character will ever change his clothes. (in all screens and videos he's with same clothes)