They are also the worst because you get mostly UVA since UVB has a harder time penetrating through cloud cover
replyI have always heard sunny snow days are the worst, because you feel cold, but the sun is still hitting you, plus reflecting off the snow to hit you twice.
replyYou can get sunburn from light reflecting off water as well, in hot places. Maybe not on its own, but certainly in conjunction with direct sunlight.
replyDepends which part of the world you are in. I've never been sunburnt on an overcast day where I live.
replyOne of my worst sunburns was in San Diego on an extremely gray day. I should have known better.
replyThe right thickness marine layer can make the sky seem dim but it's like one massive UV diffuser from horizon to horizon.