Dew-point at 2m in hPa/h
The dew-point is the temperature air would have to be cooled to in order for
saturation to occur. The dew-point temperature assumes there is no change in
air pressure or moisture content of the air. Dew-point does not change with
temperature of the air; very much different from relative humidity.
The dew-point can be used to forecast low temperatures. The low will rarely
fall far below the observed dew-point value in the evening (unless a front
brings in a different air mass). Once the temperature drops to the
dew-point, latent heat must be released to the atmosphere for the
condensation process to take effect. This addition of heat offsets some or
all of further cooling.