Officially, it cocktail. Unofficially though, wear something that lets you feel comfortable and cool(both physically and emotionally). We'll be spending a bit of time outside for ceremony so be prepared for warm sun.
Will we be on the beach?
To keep the ceremony accessible to everyone with varying physical ability to deal with the sand we're opting to keep it on the deck which overlooks the beach. Guests are welcomed and encouraged to enjoy the sand though!