In April, UV radiation in Kiel can already assume medium values.
At noon time the height of the sun rises from 40° in early April up to
50° at the end of the month. Since UV radiation at ground level highly depends
on the altitude of the sun, in case of cloudless skies UV index reaches values from 3
up to 5. Also because in April the skin often is not used to UV radiation,
protective measures are required in any case...