Abstract: In an onboard air conditioning system, a light source (25) for conditioned air is provided in association with an air outlet (31), and the color of the light emitted from the light source changes in dependence on the temperature of the conditioned air. The light source may consist of a linear light source at least partly surrounding the air outlet. Thereby, the vehicle occupant can visually recognize the operating condition of the air conditioning system. The air outlet may be at least partly-surrounded by an annular duct (20) defining a central chamber (21) that has a closed bottom and an open top defining the air outlet, the annular air duct being provided with a communication hole (23) communicating an interior of the annular duct with the central chamber, and the air outlet is covered by an air permeable sheet (30).