WHY is it better to breathe through the nose in the cold?

 The nasal cavity has the unique capability to regulate the temperature of inhaled air. When the temperature outside is -25°C, the air in the nasal cavity can be warmed up to 35-36.6°C. This heating is much more efficient than in the oral cavity. The nasal cavity serves as a built-in heating system, ensuring proper functioning of the lower respiratory tract.