Question

Reason for smoke form while breathing in winter
Why does smoke formation occur when we breathe out air in winters?

Answer 1

 What comes out of your mouth is not smoke, it's condensation. When you blow air out of your mouth, the moisture that comes out is at your body temperature. When it hits the colder air outside, the moisture follows the laws of conversion (the laws of a substance going from a gas, to a liquid, to a solid or vice versa when the temperature reach various points, such as the freezing and the boiling point) and condenses into a liquid or freezes into a solid (depending on how cold it is outside of the body).