Dangerous, long-lasting heat remains across the Mid-South to Mid-Mississippi Valley, while heat expands into the Northeast for a brief period on Friday. Strong to isolated severe thunderstorms and heavy rain pose a flash flooding threat from from the southern High Plains east to the Great Lakes. Tropical Depression 12W brings heavy rain to Guam & the Marianas through Saturday. Read More >
UV index values for the following cities:
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About the UV Index:
The National Weather Service works with the Environmental Protection Agency, to forecast the Ultraviolet (UV) Index for the U.S.
The UV index is a measure to help you determine the effects of the sun on outdoor activities. It is computed using forecast ozone levels, cloudiness, and elevation. Values are effective at solar noon, which is when the sun is at its highest point of the day. (Solar noon generally does not correspond to the clock time of 12:00 noon.) Overexposure during days with high UV values can be harmful, both in the short term and over the long term. Exposure to surface objects that reflect light (such as sand and water) can make the UV index even higher in such locations.
The UV Index runs on a scale of 1 to 11+:
UV Value and Category |
Effects |
1-2 |
A UV Index reading of 2 or less means low danger from the sun's UV rays for the average person:
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3-5 |
A UV Index reading of 3 to 5 means moderate risk of harm from unprotected sun exposure.
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6-7 |
A UV Index reading of 6 to 7 means high risk of harm from unprotected sun exposure. Protection against sun damage is needed.
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8-10 |
A UV Index reading of 8 to 10 means very high risk of harm from unprotected sun exposure. Protection against sun damage is needed.
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11+ |
A UV Index reading of 11 or higher means extreme risk of harm from unprotected sun exposure. Try to avoid sun exposure during midday hours, from 10 a.m. to 4 p.m. Apply sunscreen with an SPF of at least 30 liberally every 2 hours.
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By visiting the EPA's Sunwise page at https://www.epa.gov/sunsafety , you can get UV index values for other locations by entering specific cities or ZIP codes. You can also access nationwide maps of UV index values for the next 4 days.
UV Safety: Stay Safe in the Sun