Why Does Your Nose Run in Cold Weather? Causes Explained
Your nose runs in the cold because it adds moisture to chilly air and reacts to the temperature drop. Here is what happens inside and when to see a doctor.
Your nose runs in cold weather because the lining of the nose reacts to cold, dry air by making more mucus, and because the warm, moist air you breathe out condenses into liquid when it meets the cold surfaces inside your nose. The result is a clear, watery drip that has nothing to do with an infection in most cases. It usually stops within minutes of getting back into a warm room.
What does the nose do with the air you breathe in?
The nose warms and moistens incoming air before it reaches the lungs. The lining of the nose is full of small blood vessels close to the surface, and it is covered with a thin layer of mucus. Air passing over this surface picks up heat and water vapor within a fraction of a second.
In winter this job is harder. Cold outdoor air holds very little moisture, so the nose has to supply much more water than usual. To do that, the glands in the lining produce extra fluid. Part of that fluid ends up dripping from the front of the nose.
Why does cold air make the nose produce more mucus?
Cold, dry air irritates the nasal lining, and nerves in the nose respond with a reflex that tells the mucus glands to work harder. This is an automatic reaction of the nervous system, similar in kind to the way pepper makes you sneeze. You do not control it, and it does not require a virus or an allergen.
The blood vessels in the lining also widen in response to the cold, which brings more warm blood to the surface and makes the tissue slightly swollen. Doctors call a runny nose with no infection or allergy behind it non-allergic rhinitis, and the cold-triggered kind is sometimes nicknamed "skier’s nose."
Does exhaled breath play a part?
Yes. The air you breathe out from your lungs is warm and saturated with water vapor. When it travels back out through a nose that has been chilled by outdoor air, some of the vapor cools and turns back into water, the same way a cold glass collects droplets on a warm day. The same process fogs your breath into a visible cloud outdoors.
That water mixes with mucus and gathers at the nostrils. This is one reason the drip often gets worse when you walk from a heated building into freezing air, and why it eases when the nose warms up again.
Why do your eyes water at the same time?
Tears drain out of the eyes through two tiny channels in the inner corners of the eyelids, which lead into the nose through the tear ducts. Cold wind makes the eyes produce more tears, and the extra fluid flows down these channels and into the nasal passages. A nose that runs while the eyes are watering often has this connection to thank.
If you wear glasses or sunglasses outdoors, you may notice both symptoms ease a little, because the lenses shield the eyes from wind.
Is a runny nose in the cold a sign of a cold virus or allergies?
A runny nose in the cold alone is usually not a sign of either. Cold-triggered dripping tends to be thin, clear and watery, and it comes and goes with the temperature. A cold virus brings other symptoms: sore throat, cough, tiredness, sometimes a fever, and thicker mucus that lasts several days. Allergies usually bring itching and repeated sneezing.
Winter also pushes people indoors, where dust, pet dander and viruses spread more easily. A nose that runs mainly indoors, or that keeps running for days, may have a different cause.
- Clear, watery drip that starts outdoors and stops indoors: typical of the cold-air reflex.
- Thick yellow or green mucus, facial pain or fever: more likely an infection.
- Itchy eyes and bursts of sneezing: more likely an allergy.
When should a runny nose be checked by a doctor?
A runny nose should be checked by a doctor or other health professional when it lasts for weeks, when it appears on one side only, when it comes with a fever or severe facial pain, or when the discharge contains blood or has a bad smell. A runny nose that follows a head injury also needs urgent medical attention. In babies and young children, a nurse or pediatrician can say whether breathing or feeding is affected.
The U.S. National Library of Medicine explains runny noses and their common causes on its health topics site, MedlinePlus, which is a good place to read more about symptoms. This article gives general background and is not a substitute for medical advice.
Is the cold the only thing that makes the body react this way?
The nose is one of several places where the body responds to a drop in temperature. Shivering, goosebumps and narrowed blood vessels in the skin are other responses, and they all work to protect core body heat. The article on why we shiver and how the body makes heat describes how muscles produce warmth when the cold is more severe.
People who spend long hours outdoors in winter, such as skiers, runners and outdoor workers, tend to notice the drip most. Anyone who checks the forecast before heading out can read up on how weather forecasts work.
Quick answers
Is a runny nose in cold weather normal?
Yes. It is a common, harmless reaction in most people, caused by the nose adding moisture to cold air and by breath condensing inside the nostrils.
Why does the drip stop when you go indoors?
The nasal lining warms up, the cold stimulus disappears and the extra mucus production slows down. Condensation from your breath also stops once the nose is no longer cold.
Can the cold air itself make you sick?
Cold air does not cause a cold. Colds are caused by viruses. Winter simply puts more people in close indoor contact, which gives those viruses more chances to spread.
Why do only some people get a very runny nose in the cold?
Nasal lining sensitivity varies from person to person. People with allergies, asthma or an existing sensitive nose tend to react more strongly, but even people with no such conditions get a runny nose in freezing air.
