UV-B, the frequency range of ultra-violet light that causes sunburn, is absorbed by water but you need a few metres of it to provide adequate protection.
Half a metre of water will still let 40 per cent of the UV-B through and the cooling effect of the water makes you less aware of the Sun.
Can ultraviolet radiation travel through water?
UV light that has wavelengths longer than 200 nm passes through liquid water, while shorter wavelengths are strongly absorbed by liquid water. Sunburn is thus still a concern underwater, at least in pure water.
Can you tan through water?
As you go deeper, the rays get scattered, just as water can scatter normal light, and it gets darker the deeper you go. As long as you can still see light underwater, you are still getting hit by UV rays. Yes, ultraviolet (UV) irradiation (which is what makes you tan or burn) can penetrate the water.
What materials can block UV rays?
Construction: Like color, the material, weave and texture of your clothing can affect how well it protects you from UV rays. Synthetic and semisynthetic fibers like polyester or rayon are the best choices for sun protection, as are dense, heavy, tightly woven fabrics like wool, denim or corduroy.
Do house windows block UV rays?
A single-pane window lets in 90 percent of UV radiation and a standard double-pane window lets in over 80 percent. Museum Grade window inserts block 98 percent of the ultraviolet radiation from damaging your belongings through your windows.