The UV Index provides a forecast of the expected risk of overexposure to UV radiation from the sun. The National Weather Service calculates the UV Index forecast for most ZIP codes across the U.S., and EPA publishes this information. The UV Index is accompanied by recommendations for sun protection and is a useful tool for planning sun-safe outdoor activities.
Ozone depletion, as well as seasonal and weather variations, cause different amounts of UV radiation to reach the Earth at any given time. Taking these factors into account, the UV Index predicts the level of solar UV radiation and indicates the risk of overexposure on a scale from 0 (low) to 11 or more (extremely high).
Source: United States Environmental Protection Agency
