This one has been done recently.Wear sunglasses, they look sophisticated. A pair of flip flops with shorts but make sure they are ironed and preferably not football shorts. Wear a hawaiin shirt with a sun hat, the hawaiin shirt wrapped around your waist is permitted if it is very hot but lots of sun cream is essential. This will display that you dress appropriately for the weather and will impress any recruiting SNCO.
As said smart clothes will be ok on first visits but your recruiting staff will note what your wearing and first impressions last. As long has your not wearing anything with sexist/rascist or offencive comments on you will be ok. You should be gradually wearing smarter clothes as you go through the application then when you get to the first of your interviews wear a suit and tie, thats when we start to account for what you wear.
Good Luck to you and remember to practice the questions at least a couple of times before you go.