that is not polyester! Sleeveless or short sleeves, either is okay, as long as it is summer heat tolerable. I really want something that is a step up from a classic T shirt...something long or assym hemmed, and flowy. But T shirt type might be okay too, if the cut is loose and drapey looking.
Truly, I think this may be asking too much. Every one I have looked at that is lightweight enough for summer is see-through because of that. If it isn't see-through it is because the material is heavy enough to be hot. I'm not sure what would solve this conundrum, but if you've seen such, let me know!