Why smoke comes from the Mouth during Winter Season?
In winter season, white smoke comes out of the mouth when we speak. That too, smoke comes out of the mouth especially in the early mornings of winter season. Water vapor present in the inhaling air would be sufficiently cool in winter season in general. Irrespective of season, the exhaled air contains water vapor along with air.
Oxygen present in the inhaled air is absorbed by the hemoglobin present in the blood vessels of lungs. Exhaled air coming out contains carbon dioxide made in the body and little content of water vapor. In that way when a person exhales, some water vapor goes out in the form of smoke. But this can be seen only in the winter season. It cannot be seen in other seasons. The smoke appearing as white vapor is just water drizzles but not water vapor.