An air conditioning system for an automotive vehicle includes a duct through which conditioned air is directed into a compartment for passengers. A control device is associated with the duct for operating in a first mode discharging the conditioned air in the form of concentrated currents toward the passengers, in a second mode discharging the conditioned air in the form of diffused currents toward the passengers, and in a third mode in which switching is performed between the first and second modes at variable time intervals. One of the first, second and third modes is selected according to sensed values of compartment temperature and insolation intensity.