The power of sun radiation depends on the geographic position and the season. It is ordinary most intensive in the time between 11°° and 15°° o clock.

The skin is exposed to warming infrared radiation as well as to UV-A and UV-B radiation. The UV-B radiation is rich on energy and therefore harmful when to much. This means i.e. sunburn, skin folds and skin aging as well as a higher risk of cancer. Dermatologists register annual about  100.000 new patients of skin cancer – that is the double number than 10 years ago.