Why do I still get sunburnt on a cloudy day?
It is possible for UV radiation to pass through clouds. The amount of UV radiation that gets through depends on how thick the clouds are. Heavy cloud reduces UV levels. UV levels on lightly overcast days can be similar to that of a cloud-free day. UV levels rise and fall as clouds pass in front of the sun on a day of scattered cloud. On a cloudy day, try checking the real time UV graph to see the effects.
