A temperature probe (42), such as for a respiratory system (10) in which breathable gases are supplied to a patient, includes a housing (62) having a cavity (66) sized to snugly receive therein a generally cylindrical container (68) within which is secured a thermistor (70), with the container adapted to provide a barrier to moisture. The probe provides a quick temperature response but minimizes migration of moisture to the thermistor notwithstanding the high temperature and heat levels encountered in normal operation of the respiratory system (10).