What sorts of clothing should I bring?
Both men and women in Puerto Rico dress more formally than we are accustomed to in most US locations. Women usually wear skirts or dresses (knee-length or longer), but may wear nice slacks, and they wear shirts with at least short sleeves. They often wear a light jacket or sweater as well. Men wear trousers or, sometimes, khakis, and button-down shirts (usually long-sleeved). Of course, this varies depending on the type of work people do, and will vary for you, depending on what type of project you are doing.
While you need to be aware and respectful of local dress, you do not need to emulate it. You should check with your liaisons to determine what sort of attire is appropriate for work; men may be able to wear long shorts and women can probably wear sleeveless shirts. It is also wise to speak with previous project center participants about this, and if you are scheduled to go to Puerto Rico, you are likely to have this opportunity before you leave.
When you are not at work, you may wear whatever you find comfortable, but remember that your dress will be noticed by other people. It is still unwise to wear clothing that is revealing, except when at the beach.