A system and method of determining the temperature of a rotating electromagnetic machine, such as an electric motor or generator. A temperature calibration parameter is calculated based on the temperature of an object situated close to the motor, such as a motor drive connected to the motor, and a first resistance value of the winding. In exemplary embodiments, the motor drive and first resistance value are determined only after the motor has been idle for some predetermined time period. Once the calibration parameter is calculated, the processor uses it along with subsequent resistance measurements to calculate the temperature of the motor.