likely to be bombarded with mandates from above. Baseball caps are very "in" these days. They keep the sun out of your eyes so you can keep them on the ball (seems to work for golfers). Straw or sun hats may be all you need-just to protect you from the spotlight that may be shining on your project. And of course, there are always helmets, which may save you from head injury if and when your project takes a serious spill. There are some countries and states, which don't require helmets, citing they would interfere with personal freedom.
So now let your imagination run wild. Selecting your team's wardrobe for your next project is no small task. You may even want to review those previous project retrospectives lying around on the shelves to give you some ideas.
What type of attire does YOUR team require?