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UV index

The UV index forecasts the intensity of ultraviolet (UV) light for any given day. The index helps people know what precautions to take to avoid sunburn or other skin damage from being in the sun too long.

The UV index is listed on the weather page of many daily newspapers. Sun protection measures, such as wearing sunscreen, should always be taken when the UV index is 5 or above. The UV index is measured on a scale of 0 to 10+.

  • 0 to 2: Minimal exposure to UV rays is expected for that day. Most people can stay in the sun for up to 1 hour during the hours of the day when the sun's rays are strongest, 10:00 a.m. to 4:00 p.m.
  • 3 to 4: Low exposure is expected for that day. Fair-skinned people may sunburn in less than 20 minutes of sun exposure.
  • 5 to 6: Moderate exposure is expected for that day. Fair-skinned people may sunburn in less than 15 minutes of sun exposure.
  • 7 to 9: High exposure is expected for that day. Fair-skinned people may sunburn in less than 10 minutes of sun exposure.
  • 10+: Very high exposure is expected for that day. Fair-skinned people may sunburn in less than 5 minutes of sun exposure.
Author Jeannette Curtis
Author Caroline Rea, RN, BS, MS
Editor Kathleen M. Ariss, MS
Editor Susan Van Houten, RN, BSN, MBA
Associate Editor Tracy Landauer
Associate Editor Pat Truman
Primary Medical Reviewer Patrice Burgess, MD
- Family Medicine
Primary Medical Reviewer Adam Husney, MD
- Family Medicine
Primary Medical Reviewer Kathleen Romito, MD
- Family Medicine
Last Updated May 25, 2007

WebMD Medical Reference from Healthwise

Last Updated: May 25, 2007
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.