What Is the UV Index
The ozone layer shields the Earth from harmful UV radiation. Ozone depletion, as well as seasonal and weather variations, causes different amounts of UV radiation to reach the Earth at any given time. The UV Index is a daily forecast of the UV radiation levels people might experience. The Index predicts the next day's levels on a 0 to 10+ scale, helping people determine appropriate sun protection behaviors.
0 to 2 Minimal
A UV Index reading of 0 to 2 means minimal danger from the sun's UV rays for the average person:
Most people can stay in the sun for up to one hour during the hours of peak sun strengths, 10 a.m. to 4 p.m., without burning.
People with very sensitive skin and infants should always be protected from prolonged sun exposure.
Snow and Water Can Reflect the Sun's Rays
Skiers and swimmers should take special care. Wear sunglasses or goggles and apply sunscreen with SPF of at least 15. Remember to protect areas that could be exposed to UV rays by the sun's reflection, including under chin and nose.
3 to 4 Low
A UV Index reading of 3 to 4 means low risk of harm from unprotected sun exposure. Fair-skinned people, however, might burn in less than 20 minutes:
 | Wear a hat with a wide brim and sunglasses to protect your eyes. |
| Use a sunscreen with an SPF of at least 15 and wear long-sleeved shirts and long pants when outdoors. |
An easy way to tell how much UV exposure you are getting is to look for your shadow:
If your shadow is taller than you are (in the early morning and late afternoon), your UV exposure is likely to be low.
If your shadow is shorter than you are (around midday), you are being exposed to high levels of UV radiation. Seek shade and protect your skin and eyes.
5 to 6 Moderate
A UV Index reading of 5 to 6 means moderate risk of harm from unprotected sun exposure. Fair-skinned people might burn in less than 15 minutes. Apply a sunscreen with an SPF of at least 15. Wear a wide-brim hat and sunglasses to protect your eyes:
Use sunscreen if you work outdoors and remember to protect sensitive areas like the nose and the rims of the ears. Sunscreen prevents sunburn and some of the sun's damaging effects on the immune system.
Use lip balm or lip cream containing a sunscreen. Lip balms can help protect some people from getting cold sores.
7 to 9 High
A UV Index reading of 7 to 9 means high risk of harm from unprotected sun exposure. Fair-skinned people might burn in less than 10 minutes. Minimize sun exposure during midday hours, from 10 a.m. to 4 p.m. Protect yourself by liberally applying a sunscreen with an SPF of at least 15. Wear protective clothing and sunglasses to protect the eyes:
When outside, seek shade. Don't forget that water, sand, pavement, and grass reflect UV rays even under a tree, near a building, or beneath a shady umbrella.
Wear long-sleeved shirts and trousers made from tightly woven fabrics. UV rays can pass through the holes and spaces of loosely knit fabrics.
Be careful during routine outdoor activities such as gardening or playing sports.
Remember that UV exposure is especially strong if you are working or playing between the peak hours of 10 a.m. and 4 p.m. Don't forget that spectators, as well as participants, need to wear sunscreen and eye protection to avoid too much sun.
10+ Very High
A UV Index reading of 10+ means very high risk of harm from unprotected sun exposure. Fair-skinned people might burn in less than 5 minutes. Outdoor workers are especially at risk as are vacationers who can receive very intense sun exposure. Minimize sun exposure during midday hours, from 10 a.m. to 4 p.m. Apply sunscreen with an SPF of at least 15 liberally every 2 hours:
Avoid being in the sun as much as possible.
Beat the Heat
If possible, stay indoors on days when the UV Index is very high. Take the opportunity to relax with a good book rather than risk dangerous levels of sun exposure. Try not to pursue outdoor activities, whether at work or at play, unless protected with sunscreen, hat, and sunglasses.
For more information about the UV Index, contact EPA's Stratospheric Protection Hotline at (800) 296-1996 or the UV Index Web site at www.epa.gov/ozone/uvindex/uvover.html.
National Safety Council
1025 Connecticut Avenue, NW, Suite 1200, Washington, DC 20036
(202) 293-2270 (tel); (202) 293-0032 (fax)
