The second-generation Mercedes CLS can be optionally fitted with an automatic climate control system which not only allows individual temperatures to be set for three zones - for the driver, the front passenger and the rear passengers - but additionally offers special climate modes. This means that, if the optionally available THERMOTRONIC system is fitted, the car occupants can select "Diffuse", "Medium" or "Focus" settings on the THERMOTRONIC at the push of a button and thus adjust the air quantity and air distribution to their liking without having to leave the convenient automatic mode.

In "Diffuse" mode, for example, the THERMOTRONIC system operates with a lower air speed and distributes the air over a wide area so that there are fewer draughts. This is the purpose of the automatically controlled, upwards inclined diffuse nozzle in the centre of the dashboard. In "Focus" mode, meanwhile, the air outlets in the centre area of the dashboard are used for the most part, meeting the need for a direct flow of a larger quantity of air. The standard system fitted in the CLS is the two-zone THERMATIC automatic climate control.