psychrometrics (PSY) [%]

Psychrometrics (or psychrometry, from Greek ψυχρόν (psuchron) 'cold' and μέτρον (metron) 'means of measurement'; also called hygrometry) is the field of engineering concerned with the physical and thermodynamic properties of gas-vapor mixtures. (Wikipedia, CC BY-SA)

A psychrometric chart is a graph of the thermodynamic parameters of moist air at a constant pressure, often equated to an elevation relative to sea level.

La psychrométrie est le domaine scientifique concernant la détermination des caractéristiques physiques et thermodynamiques d'un mélange gaz-vapeur correspondant à deux espèces différentes. (Wikipedia, CC BY-SA)