Why do we get runny noses in the cold?

Question

The most annoying thing for me about being cold is a runny nose. Is there an advantage to having a runny nose when cold? What does having a runny nose achieve?

Answer 1

There are two reasons for this:

1. Nasal mucus helps warm inhaled air before it reaches the lungs. In cold weather, the mucus tends to dry out, so the membranes increase their production.
2. At the same time, exhaled air is warmer than the surrounding air, so it contains more moisture than the outside air can hold. This moisture condenses around the tip of the nose.

Explanation found here.

So there's no particular advantage to getting a runny nose; it's just a normal reaction occurring in extreme conditions.