An analytic expression for saturation vapor pressure

e

s {\textstyle e_{s}} given as a function of temperature by

e

s ( T )

0.611 ×

10

7.5 T ( T + 237.3 ) {\displaystyle e_{s}(T)=0.611\times 10^{7.5T(T+237.3)}}

where the temperature T is given in °C and the vapor pressure is in kPa. A slightly improved version is shown under Clausius–Clapeyron equation.

Tetens, O. 1930. Uber einige meteorologische begriffe. Z. Geophys., 6, 297–309.

Term last updated 23 February 2026