A thermostat includes a memory configured to store operating conditions for previously run conditioning events. The thermostat further includes a controller configured to receive first temperature data from a first temperature sensor indicative of a current indoor ambient temperature inside; receive second temperature data from a second temperature sensor indicative of a current outdoor ambient temperature outside; receive a temperature setpoint for a desired indoor ambient temperature of the building; determine a severity of a call for conditioning based on at least one of the current indoor ambient temperature, the current outdoor ambient temperature, and the temperature setpoint; and operate the multi-stage HVAC system in one of the plurality of stages for a current conditioning event based on the severity of the call for conditioning and the operating conditions for a similar previously run conditioning event to drive the current indoor ambient temperature towards the temperature setpoint.