Abstract: The disclosure generally relates to method and apparatus for predicting the steady state temperature of solid state devices, preferably under transient conditions. An apparatus according to one embodiment of the disclosure includes a thermocouple for detecting temperature of the solid state system; a processor in communication with the thermocouple and programmed with instructions to: construct an initial curve for the solid state system, the initial curve having a shape; obtain a plurality of theoretical temperature curves for the solid state system; select one of the plurality of theoretical temperature curves having a shape closest to the shape of the initial curve; and superimposing the selected theoretical temperature curve on the initial curve to predict the steady state temperature.