A thermostat includes at least a housing, a user interface, a memory, an environmental sensor, and a processing system. The processing system may be configured to operate in a wake state and a sleep state by determining wake-up conditions upon which the processor is to enter into the wake state from the sleep state that includes a threshold value associated with an environmental condition sensed by the environmental sensor, causing the wake-up conditions to be stored in the memory, operating in the sleep state during a time interval subsequent to causing the wake-up conditions to be stored in the memory, determining whether at least one of the wake-up conditions has been met, and operating in the wake state upon a determination that the at least one wake-up condition has been met.