Normand's theorem

From Glossary of Meteorology



Normand's theorem

A theorem in psychrometry that states that the dewpoint temperature is always less than or equal to the wet-bulb temperature, which is always less than or equal to the dry-bulb temperature.

It is not, however, true in supersaturated air or for air temperatures below freezing if the wet bulb is frozen and the air is supersaturated with respect to ice.