SUUSI is summer casual. Most of the time you'll see everyone dressed in t-shirts and shorts. Evening wear is often the same, though some will dress up in slacks and polo shirts, or blouses and skirts, for evening events. And fun-to-wear costumes are encouraged - it's vacation time, time to have some fun and stretch a little. Who says you have to wait until Halloween or a debutante party to dress up?
Remember, sometimes the weather at SUUSI turns cool, so it is wise to pack a pair of jeans and a jacket, just in case.