Here's why:

* Condensation: This is the process of a gas (water vapor) changing into a liquid (water).

* Hydrogen Bonds: Water molecules are attracted to each other due to strong hydrogen bonds. These bonds form between the slightly positive hydrogen atoms of one water molecule and the slightly negative oxygen atom of another.

* Energy Release: When water vapor condenses, the water molecules slow down and come closer together. This requires energy to be released, and that energy is in the form of heat.

Think of it this way: The water molecules in the air are moving fast and have a lot of energy. When they condense, they slow down and get closer together, releasing that extra energy as heat.