People wear just what any high school student would wear. Whatever you see on the street. Jeans T shirts, dresses, skirts, shorts, etc. There are many different styles and for the girls it seems the majority wear ugg boots and yoga pants. Guys are guys and wear jeans and t shrits. The style here isn't anything too unusual.
People will wear anything from gym shorts or sweat pants and an old t-shirt or sweatshirt, to designer jeans and really preppy clothes. The general rule is the earlier the class the more relaxed people dress. In the early fall and late spring when its hot make sure to dress comfortable.