Can you actually catch a cold from being cold?
The Real Answer
Cold weather itself does not give you a cold. A respiratory virus does. More than 200 respiratory viruses can cause cold symptoms, with rhinoviruses being the most common cause in the United States. You can catch one at any time of year.
But the old belief isn't completely disconnected from biology. Research has found that cooler temperatures in the nose can make conditions more favorable for some cold viruses and can weaken parts of the nose's local antiviral defenses. That may help explain why respiratory infections are more common during colder seasons—but you still need to encounter a virus. Going outside with wet hair does not generate one.
We’ve been running the same half-assed folk remedy for 400 years: “Wear a coat or you’ll get sick,” said with such confidence that nobody bothered to check if it was true. Cold doesn’t infect you. But try explaining germ theory to your mother while standing outside without a coat—she’ll accept the science right after you put on a hat.
The Dunce Dynamics Institute Examines Why People Ask This
The belief survives because colds really are more common in colder seasons, so temperature and infection are easy to fuse into one cause. The missing piece is that a respiratory virus still has to be transmitted.