A thermostat may include one or more temperature sensors, and a processing system configured to be in operative communication with an HVAC system. The processing system may be configured to operate a first operating state characterized by relatively low power consumption and a corresponding relatively low associated heat generation, and a second operating state characterized by relatively high power consumption and a corresponding relatively high associated heat generation. During time intervals in which the processing system is operating in the first operating state, the processing system may process the temperature sensor measurements according to a first ambient temperature determination algorithm to compute the determined ambient temperature. During time intervals in which the processing system is operating in the second operating state, the processing system may process the temperature sensor measurements according to a second ambient temperature determination algorithm to compute the determined ambient temperature.