Dew point temperature

Dew point temperature: Tdp [°C]

It is the temperature detectable for a given state of wet air at saturation for specific absolute humidity x. In the h-x diagram we draw a vertical line along a constant absolute humidity (x = constant) down to the saturation curve (RH = 100%) and at this point the isotherm at the intersection indicates the dew point temperature Tdp. For Tdp < 0°C it is needed to consider as a Frost Point Temperature, Tfp.