If the air has a Pressure Dew Point (PDP) of -40°C, it indicates that the air is extremely dry and can hold very little moisture before condensation occurs. However, the PDP itself does not directly indicate the temperature of the air.
Air temperature and the dew point temperature are related but separate measurements. The dew point temperature is the temperature at which the air becomes saturated with moisture and condensation begins to form. If the air temperature is equal to or lower than the dew point temperature, condensation will occur.
So, if the air has a PDP of -40°C, it means that the air can hold very little moisture before it reaches a saturation point and condensation starts to form at or above -40°C. The actual temperature of the air could be higher or lower than -40°C.
In general, a PDP of -40°C indicates extremely dry air, but it doesn’t necessarily mean that the air itself is freezing cold. The actual air temperature would determine whether it is freezing cold or not.