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Clear-sky UV index for 31 Dec 2025 With a thinner ozone layer and a higher position of the sun in the sky more ultraviolet radiation will reach Earth’s surface. The clear-sky UV index is the effective UV irradiance (1 unit equals 25 mW/m²) reaching the Earth’s surface. The clear-sky UV index is based on the CIE action spectrum for the susceptibility of the caucasian skin to sunburn (erythema) and it is valid for cloud-free conditions at local solar noon. Forecasts are provided for today and the next few days.

8 Day Forecast  (show last 8 days)

1 Jan

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3 Jan

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7 Jan

8 Jan

Ronald van der A, Bas Mijling © KNMI/TEMIS, 2019