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Optical Radiation

UV Radiation - Sun - Solaria - Infrared Radiation - Laser

Optische Strahlung

UV Index

The UV Index (UVI) is internationally standardized. It is a measure of the intensity of UV radiation reaching the earth's surface on a horizontal area, weighted according to the risk of sunburn.

What is the UV Index?

The UV Index describes the expected daily peak level of the erythemal UV irradiance at ground level.

UV Index worldwide

Typical UV Index values in various countries worldwide, calculated with the radiation transfer programme STAR at the 21st of each month.



UV index forecasts are issued every 3 days each year from April to September by BfS, in cooperation with the Federal Environment Agency (Umweltbundesamt), Germany's National Meteorological Service (Deutscher Wetterdienst, DWD) and other associated institutions. The UV index is the internationally standardised measure of the daily peak value of erythemal UV radiation expected to reach the Earth’s surface. The higher the UVI value, the less time it takes for sunburn to occur on unprotected skin.


UV monitoring network

The incident solar radiation is continuously measured at twelve stations in the Federal Republic of Germany with finite instrument resolution of the wavelength.

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