Dress for 75-85F weather with 100% humidity.
The warm weather makes mildew grow easily.
You can expect a downpour almost every afternoon unless there is a storm, then it can be all day. It can rain an inch an hour but it is usually short.
Waterproof clothes may be sweaty and uncomfortable. Light clothes that dry quickly may be better.
Light shirts and swimsuits. Sandals, think beach wear without too many beaches.
You can buy a lavalava to wrap over your swim suit there.http://www.world66.com/australiaandpacific/americansamoa/climate
Picture shows boys in school uniform, good attire for everyone