MODEL RELEASED. Breath condensing in cold air. Boy watching the water vapour in his breath condensing into mist on a cold winter's day. Air breathed out from the warm, moist environment of the lungs is saturated with water vapour. When the surrounding air is cold, this water vapour briefly condenses into small droplets of liquid water that form a visible cloud of white mist before fading as the droplets evaporate into the much greater volume of air outside the lungs.