An auto changeover mechanism for a thermostat. A heat and cool mode auto changeover with single or crossed setpoints may be an approach for doing a single setpoint auto changeover, an approach that can handle auto changeover with separate heat and cool setpoints that do not require the cool setpoint to always be higher than the heat setpoint, and also an approach that does not necessarily require a dead band between the setpoints. A hysteresis may be associated with switching to the other mode. The thermostat having the auto changeover mechanism may have a display of a mode that automatically changes between heat and cool.