Pack breathable, lightweight layers that dry fast in humidity. For a week in the tropics, bring five to seven onesies or playsuits in muslin cotton, a couple of loose sets for cooler evenings, and a soft hat for sun. Muslin's open weave keeps air moving and dries quickly between wears or washes.
Packing for heat and humidity is different from packing for anywhere else. You want fabric that lets air through and doesn't stay damp, because a hot climate means more sweat and more washing than usual. We make our muslin pieces with exactly that kind of week in mind.