A method of determining an initial temperature of an ultrasonic blade may include measuring a resonant frequency of an ultrasonic blade prior to activating an ultrasonic transducer, in which the ultrasonic transducer is coupled to the blade via an ultrasonic waveguide, comparing the measured resonant frequency to a baseline resonant frequency, determining an initial temperature of the ultrasonic blade based on a difference between the measured resonant frequency and the baseline resonant frequency, and applying a power level to the blade based on the initial temperature of the blade. The method may further include applying a high power level to the transducer when the initial temperature of the ultrasonic blade is low or applying a low power level to the transducer when the initial temperature of the blade is high. The baseline resonant frequency may be stored in a memory look up table.
