What is the dew point?

The dew point is defined as the temperature to which humid air must be cooled at constant pressure in order to become saturated. This means that when the air reaches this temperature, the water vapor in it condenses into liquid water, leading to the formation of dew. The dew point is an important parameter in meteorology, as it indicates the moisture content in the air. A higher dew point signifies more humidity, while a lower dew point indicates drier air.

Understanding the dew point is crucial for predicting weather patterns and phenomena such as fog, cloud formation, and precipitation. When air cools to its dew point, it reaches 100% relative humidity, which is when condensation occurs. This helps explain why the other choices do not accurately reflect the concept: while some options touch on aspects of humidity or temperature, they fail to describe the specific point of saturation that defines the dew point.