You shouldn't have a problem. If you want, you can wait till December to start planting, but come May or so, put out those tomatoes and herbs. Just water them a LOT and they'll do fine. All the mediterranean veggies will do well in the really hot months, then the Scandinavian veggies will do fine in the "winter" months. Check the library for books on California gardening, they do exist. Remember, California is a primarily agricultural state for a reason.