Why is a swimming pool a good place to cool off?

It is a lot better than trying to cool off on the hot cement!

But seriously there are two factors both of which are important.

1. When you become wet and you get out of the pool it takes heat energy to dry the water so you get cooler.

2. The pool has a large heat storage capacity. It remains approximately constant between day and night.

So it is cooler than the warm air of the day.

And it absorbs heat readily which air does not. So direct transfer of heat while you are in the pool occurs.

3. in most cases the temperature of the pool and of the air is less than body temperature.

You need to lose some heat all the time. But it must be regulated.

When the air temperature gets towards body temperature the rate of cooling is not sufficient.

But the water is a better absorber of heat so it will continue to cool until it is quite close to the body temperature. Then the conditions become reversed. As in a hot bath or a hot tub.

Now look at both and consider what should happen at night

As you enter the pool the heat from your body is transferred to the water molecules giving a "Cool" sensation.

SCIENCE!