If 70 degrees Fahrenheit air feels warm and comfortable to us why does 70 degrees Fahrenheit water feel cold when you swim in it?

Answer 1

== == === === It takes longer to heat or cool water than for air. The water was probably warm from being heated by the sun all day, and so was the air. But in the evening or when there is a cloud cover, the air cools more rapidly than the water, hence the observed difference and conflict. Likewise, water that sits in the cold all night long (or for several days) stays cold for a long time, even during the first few hot days where the air is warm.

== == When you jump out of a swimming pool, the water molecules on the surface of your body escape with whatever body heat you had while in the pool. Water is an excellent conductor of heat (as opposed to an insulator) so it steals heat from your body. So you feel colder out of the pool right after you come out.

Answer 2

While both water and air are poor conductors of heat, water is 100x better than air in conductivity and instantly takes the heat from your body... That's why it feels colder then the air even though they are the same temperature