Dew point is the temperature to which a given body of air must be cooled to become saturated with water vapor. At this point, the air cannot hold more water in the gas form, and airborne water vapor will condense to form liquid water known as dew. The dew point is affected by the airs humidity, and the more moisture the air contains, the higher its dew point. When the temperature is below the freezing point of water, the dew point is called the frost point, as frost is formed via deposition rather than condensation. Dew point is an important part of weather station data because it can be used to predict the formation of dew, frost, fog, minimum overnight temperatures, and even rain, thunderstorms, and tornadoes.
Dew point is different from humidity, which is a measure of the amount of moisture in the air relative to the maximum amount of moisture the air can hold at a given temperature. The higher the dew point, the more moisture in the air, and the more uncomfortable it will feel outside. On the other hand, the lower the dew point, the less muggy the air feels. A dew point under 50 means the air is very dry, whereas a dew point between 50-60 is often thought of as the ideal comfort range for most people. Any dew point higher than 61 is considered uncomfortable and oppressive. Therefore, the dew point is a better measure of how muggy the air feels than humidity.
