Summary:
This is the 'high risk' zone and prolonged exposure can cause skin burns. "However, this summer did not have too many successive days with high UV index," he said. May 21 and May 24 reported second highest values on the index at over 8, which too falls in the high risk category. UV index is zero during the night when the sun has set. "The UV index is effectively a rough measure of the amount of harmful ultraviolet radiation in the sunlight reaching the earth's surface at a given location..