Why does the cold weather cause a runny nose? How can I prevent my nose from running on the main road? Too ugly ....

Because the air in winter is colder than other seasons, and cold air entering the nose will stimulate the nasal mucosa, thus increasing the amount of nasal water, which is the normal defense of the nose against cold air.

The most important thing is that cold air stimulates the eyes and causes tears, but if it is not too much, the liquid secreted by lacrimal gland will flow from nasolacrimal duct to nose.

Runny nose

Because nasolacrimal duct connects lacrimal gland and nose.

Haven't you heard of it? A snot and a tear? That's why, hehe.