UV radiation from the sun is always present, whether it’s a cloudy day or blazing hot outside. Some types of UV radiation can even get to you through windows, which is why it’s a good idea to wear some form of SPF every day. There are three main types of UV radiation – UVA, UVB and UVC. You don’t really need to worry about UVC as it is absorbed by the Earth’s atmosphere. UVA and UVB rays are the ones that cause serious harm by penetrating into the skin and damaging proteins, membranes and the DNA in your skin cells.