Analysis of information sources in references of the Wikipedia article "Sunburn" in English language version.
Clear skies allow virtually 100% of UV to pass through, scattered clouds transmit 89%, broken clouds transmit 73%, and overcast skies transmit 31%.
A UVB-induced tan provides minimal sun protection, equivalent to an SPF of about 3.
Up to 80% of solar UV radiation can penetrate light cloud cover.
Clear skies allow virtually 100% of UV to pass through, scattered clouds transmit 89%, broken clouds transmit 73%, and overcast skies transmit 31%.
A UVB-induced tan provides minimal sun protection, equivalent to an SPF of about 3.
Up to 80% of solar UV radiation can penetrate light cloud cover.