A breathing assistance system for delivering gases to a patient for therapeutic purposes, comprising: a humidifier comprising a humidifier chamber configured to hold a volume of water and a heater plate configured to heat the volume of water, the humidifier further comprising an inlet port and an exit port, the humidifier configured to receive a flow of gases via the inlet port, heat and humidify the flow of gases, and permit the flow of gases to exit the humidifier via the exit port, an ambient temperature sensor configured to measure a temperature of the flow of gases before the flow of gases enters the humidifier via the inlet port; a conduit configured to deliver the flow of gases to the patient via a patient interface, the conduit comprising a heater wire configured to heat the flow of gases within the conduit, a patient end temperature sensor configured to measure a temperature of the flow of gases at the patient end of the conduit, a flow sensor configured to measure a flow rate of the flow of gases through the breathing assistance system; and a controller configured to: receive data relating to the temperature of the flow of gases measured by the patient end temperature sensor, data relating to the flow rate measured by the flow sensor and data relating to the temperature measured by the ambient temperature sensor, determine a target patient end gases temperature based at least in part on the data relating to the flow rate measured by the flow sensor and the data relating to the temperature measured by the ambient temperature sensor, wherein the target patient end gases temperature varies based on a change in at least one of the flow rate measured by the flow sensor or the temperature measured by the ambient temperature sensor, compare the target patient end gases temperature to the temperature of the flow of gases measured by the patient end temperature sensor and control the heater wire to maintain or alter the temperature of the flow of gases achieve the target patient end gases temperature and achieve a desired temperature at the patient interface. a humidifier comprising a humidifier chamber configured to hold a volume of water and a heater plate configured to heat the volume of water, the humidifier further comprising an inlet port and an exit port, the humidifier configured to receive a flow of gases via the inlet port, heat and humidify the flow of gases, and permit the flow of gases to exit the humidifier via the exit port, an ambient temperature sensor configured to measure a temperature of the flow of gases before the flow of gases enters the humidifier via the inlet port; a conduit configured to deliver the flow of gases to the patient via a patient interface, the conduit comprising a heater wire configured to heat the flow of gases within the conduit, a patient end temperature sensor configured to measure a temperature of the flow of gases at the patient end of the conduit, a flow sensor configured to measure a flow rate of the flow of gases through the breathing assistance system; and a controller configured to: receive data relating to the temperature of the flow of gases measured by the patient end temperature sensor, data relating to the flow rate measured by the flow sensor and data relating to the temperature measured by the ambient temperature sensor, determine a target patient end gases temperature based at least in part on the data relating to the flow rate measured by the flow sensor and the data relating to the temperature measured by the ambient temperature sensor, wherein the target patient end gases temperature varies based on a change in at least one of the flow rate measured by the flow sensor or the temperature measured by the ambient temperature sensor, compare the target patient end gases temperature to the temperature of the flow of gases measured by the patient end temperature sensor and control the heater wire to maintain or alter the temperature of the flow of gases achieve the target patient end gases temperature and achieve a desired temperature at the patient interface.