Why you should wear a wetsuit?
There are some basic physics that we’ve seen all around us. According to the second law of thermodynamics, heat flows from warmer objects to colder ones and not vice versa. So when you are in the water, your body heat naturally escapes to the colder temperature of the water. Whats more, you will lose heat a lot faster in water, about 25 times, than in air, so the body temperature can significantly drop causing hypothermia.
This is why wetsuit comes out.