"How Colds are Transmitted"

You can make snow angels in shorts and a T-shirt, but the temperature itself won't transmit the cold virus. There are other hazards, of course, like frostbite, but a cold specifically does not come from the cold weather.

Staying warm is, however, important for children with asthma. Sometimes cold weather can spark a flare-up; for those kids, wearing a scarf over their mouth and nose helps warm the air to prevent an asthma attack, said Dr. Peter Greenspan, a pediatrician in Waltham, Massachusetts.

If, however, your friend sneezes on a snowball and throws it in your face, that could give you a cold. Or if your friend sneezes on his or her hand and touches a doorknob that you also touch, and then you rub your eye with that hand.

"You really have to actually catch the virus through a droplet from a person who's infected with the virus," said Dr. Sharon Bergquist, internal medicine specialist at the Emory University School of Medicine.

But here's why winter is particularly hazardous: Droplets from a sneeze or cough can travel farther on a cold, crisp day than on a humid one. The nasal passages get dried out in cold, dry weather, and these weather conditions also pull moisture out of droplets to allow the virus to stick around in the air longer.

Also, people come into close contact with each other more frequently in winter because they are indoors, making transmission more likely.

Viruses stay on surfaces such as telephones, doorknobs, elevators and any communal type of space, Bergquist said.

Around your house, using disinfectants such as Lysol may prevent colds from spreading, she said.

A person is contagious a few days before he or she starts noticing symptoms. There is a two- to five-day incubation period. That means if you're exposed to someone who is infected, you're probably safe if you're symptom-free about five days after you've come into contact with him or her.

Article from CNN.com