What is the UV Index?

The UV Index provides a daily forecast of the expected risk of overexposure to the sun. The Index predicts UV intensity levels on a scale of 0 to 11+, where 0 indicates a minimal risk of overexposure and 11+ means a very high risk. Some exposure to sunlight can be enjoyable; however, too much could be dangerous. Overexposure to the ultraviolet (UV) rays of the sun radiation can cause immediate effects, such as sunburn, and long-term problems, such as skin cancer and cataracts. The UV Index, which was developed by the National Weather Service and the U.S. Environmental Protection Agency (EPA), provides important information to help you plan your outdoor activities to prevent overexposure to sun rays.

The UV index and the corresponding exposure level as categorized by the World Health Organization are shown in the table on the right.


UV Index
Exposure Level
Very High
>= 11

Stillwater UV Index Forecast

UV Forecast Apr 30 2017 is 6.1
(UV forecast courtesy of and Copyright © KNMI/ESA (http://www.temis.nl/). Used with permission.)

UV forecast: Apr 30 2017 is 6.1   High 

UV forecast: May 01 2017 is 8.2   Very High 

UV forecast: May 02 2017 is 9.3   Very High 

UV forecast: May 03 2017 is 8.2   Very High 

UV forecast: May 04 2017 is 6.7   High 

UV forecast: May 05 2017 is 7.2   High 

UV Index Category Sunburn Time
over 9 extreme less than 15 minutes
7-9 high about 20 minutes
4-7 medium about 30 minutes
0-4 low more than 1 hour

National UV Index

uv map