Abstract: A computer-readable storage device stores machine instructions which, when executed by one or more central processing unit (CPU) cores, causes the one or more CPU cores to use a first ultrasonic transducer and a second ultrasonic transducer to measure fluid flow using a current measurement frequency and to perform a temperature calibration process. The temperature calibration process includes the sequentially generation of a plurality of electrical signals for the first ultrasonic transducer, the generated electrical signals each having a different frequency. For each frequency, the temperature calibration process includes the measurement of an amplitude of a signal from the second ultrasonic transducer. Based on the measured amplitudes of the signals from the second ultrasonic transducer, the temperature calibration process includes the determination of a new measurement frequency. The first and second ultrasonic transducers are used to measure fluid flow using the new measurement frequency.