A method of automatically controlling the temperature of a patient circuit (56, 58) of a pressure support system (50) includes determining (directly measuring or estimating/deriving) one or more environmental parameters relating to environmental conditions around the pressure support system, such as ambient temperature and/or ambient humidity, determining a desired temperature based on at least the one or more environmental parameters, and controlling the operation of a heating apparatus (70) operatively associated with the patient circuit based on the desired temperature. Also, a pressure support system implementing the method.