Operating method of an air conditioning device for vehicles

When driving under particularly hot weather conditions the outer surface of the windscreen can be covered by condensation when the air condition is switched on. The accumulation of moisture on the windscreen can be avoided when the dew point temperature of the air surrounding the vehicle is determined, the temperature of the windscreen estimated or measured, the difference between the results determined, and the air flow guided towards the windscreen controlled in order to keep the temperature of the screen above the dew point.