To help protect our skin from sunburns caused by UVA and UVB rays. UVC rays are short wavelength and do not reach the earth's surface.
UVB rays make up about 5-10% of the rays that reach us:
UVA rays constitute approximately 90-95% of the rays that reach the Earth:
The daily UV index forecast is a prediction of the maximum UV strength for the day, which is usually reached in the early afternoon.
Tap to zoom