The atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form. When moist air passes over a cold surface and the water condenses when it reaches its dew point temperature at the cold surface. Air can only hold so much moisture, as a function of the air temperature. Colder air can’t hold as much water vapor which condenses into water droplets at the dew point, the point that the air is saturated at 100% relative humidity. To learn more about dew point, view our blog How 3 Key Dehumidification Terms Relate.