From Pool to Rain: The Science of Indoor Humidity! Condensation is the process where water vapor in the air changes into liquid water. It occurs when warm, moist air cools down to its dew point - the temperature at which air becomes saturated and can no longer hold all its water vapor. This is why you often see droplets forming on cold surfaces, like windows on a chilly day, a cold drink on a hot day, or the ceiling of a humid indoor swimming pool. Condensation plays a crucial role in the water