i have a coolibar jacket that has a lot of ventilation is very thin fabric and i think the upf is 50 i also have a coolibar long sleeve jersey i wear in the upper 80's it rarely gets hotter than that here so have not tried hotter. both are comfortable enough in the upper 80's that i keep them on and i don't get any color on when i wear them.

i would like to see a upf rating for the cool wings the team estrogen web page recommends wearing sunscreen underneath them.

on very sunny days i wear sunscreen under whatever i have on regardless of upf rating