Patient Information

UV Exposure Categories


What is the Ultraviolet (UV) Index?

In response to the increasing incidence of skin cancer, cataracts, and other effects from exposure to the sun's harmful rays, the National Weather Service (NWS), the US Environmental Protection Agency (EPA), and the Centers for Disease Control and Prevention (CDC) collaborated on a sun-awareness information program. An important part of this program is the Ultraviolet (UV) Index, developed by the Climate Prediction Center of the National Weather Service.
The Index is a next-day forecast that estimates the amount of ultraviolet radiation that will reach the earth's surface - providing important information to help you prevent overexposure to the sun's rays. The Index also includes the effects of cloud cover on the anticipated UV exposure level for the next day.

What are the UV exposure categories?

Index Values

Exposure Categories

0 - 2

Low-An index reading of 2 or less low danger from the sun's UV rays for the average person.

3 - 5

Moderate-An index reading of 3 to 5 means a moderate risk of harm. Take precautions if you will be outside. Stay in shade near midday.


High-An index reading of 6 to 7 means you may be at high risk of harm from unprotected exposure to the sun. Wear a wide brim hat and sunglasses. Wear sunscreen, as protection against sunburn is needed. Reduce time in the sun between 11 a.m. and 4 p.m.


Very High-An index reading of 8 to 10 and above means you are at a very high risk of harm from unprotected sun exposure. Take extra precautions. Minimize exposure between 10 a.m. and 4 p..m. Cover up and wear a hat and sunglasses. Wear sunscreen.

11 +

Extreme-An index reading of 11 and above means you are at extreme risk of harm from unprotected sun exposure. Follow all of the above suggestions to protect yourself from the sun.


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