# How does a change in temperature affect relative humidity

Assume that the air pressure and the amount of water in the air stay constant. How can I figure out how much a change in temperature affects the relative humidity?

• Not sure why I can't add an answer. I came up with this formula: RH1 = pH2O*(t0) / pH2O*(t1) * t0/t1 * RH0, where RH1 is the new rel. humidity, RH0 is the old one, t0 and t1 are the temperatures, and pH2O*(t) is the equilibrium vapor pressure of water at temperature t. pH2O*(t) is defined as exp(20.386 - 5132 / t), but there are alternative formulations. All temperatures are in K, pressures are in mmHg. – Erik Allik Jan 15 '16 at 12:32