They don't know yet that...

...the water temperature is only +12 C degrees...
I know because I took my morning bath a few minutes earlier and checked the temperature afterwards. It could be worse... (and has also been it earlier this week).
For your information - there is a summer camp for 200 children and teenagers, during three weeks - every morning starts with the ritual of "swimming" in the sea. (When the temperature in the water is low, you cannot talk about swimming...)