Global clear-sky UV index 26 March 2001

Global clear-sky UV index 26 March 2001. The UV index is the effective UV-B irradiance (divided by 25 mW/m2) reaching the Earth's surface. This UV index is valid for
clear-sky conditions and will usually be lower for cloudy skies. However, under partially cloudy conditions the UV index can be higher for short time periods. The UV index can be up to a factor 2 higher when the Earth's surface is covered with snow.
(image courtesy KNMI/ESA)