WX 101: UV Index

Published 05/15 2014 12:07PM

Updated 05/19 2016 02:10PM

UV stands for ultraviolet, ultraviolet radiation is emitted from the sun to the Earth and can be damaging to skin & eyes. It can result in skin cancer and premature aging of the skin. The UV index is a measure of this harmful radiation.

The UV Index goes from Low to Extreme.

An index number at or below 2 is Low. The amount of time it will take for a sun burn averages an hour or more. With this index it is recommended to wear sunglasses on bright days and use sunscreen. Basically it is recommended that you always wear sunscreen year round under any index.

An index of 3 to 5 is Moderate. Your burn time is about 45 minutes. With a moderate index you should reduce your exposure during the most sun intensive time of the day which is 10 am to 4 pm. It is recommended you also wear a hat along with sun glasses.

An index of 6 to 7 is High. Your burn time is 30 minutes. This means protection against sun damage is definitely needed.   Along with the hat, sun glasses, and reduced time outside. You should wear long sleeves and pants instead of shorts if possible.

An index of 8 to 10 is Very High. This means your burn time is 25 minutes. Men should try to wear a shirt along with a hat and sunglasses. You should reduce time outdoors and if you must be outside, try to seek shade as much as possible.

An index of 11+ is Extreme. Your burn time is 10 minutes. You should reduce time in the sun as much as possible along with skin exposure to the sun.

A couple of things are responsible for a higher UV index. It will be higher in the summer when there is a higher sun angle. It will also be higher when there is less cloud cover, since clouds help to block the radiation. Ozone helps to block UV rays from reaching the ground, so a depleted ozone layer allows more UV to reach the Earth.

There are certain precautions you should always take to help reduce your risk of sun damage & skin cancer. Try to never burn. Put on sunscreen whenever going outside and make sure it is an SPF of at least 30 and reapply it every 2 hours. Take extra precautions near water, snow, and sand since they reflect sun rays.


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