H.W.
Everything SB said.
Something else to think about-- don't let the clouds fool you; people do get sunburnt on overcast days too. I grew up in Honolulu, but even now here in Oregon I am religious about wearing sunblock and sunhats. Yes to sunglasses, as the glare off the water is still seared into my brain all these years later! Drink lots of water, too, to prevent against sunstroke; it gets hot and humid there in the summertime.