"Bundle up! Cold weather makes you sick." Apologies to the generations of mothers who tried to convince their children of this, but you can't blame the temperature or an aversion to hats for your cold or flu. “Getting cold and damp does not have a noteworthy effect on whether or not you get sick,” says William Schaffner, M.D., of the Vanderbilt University School of Medicine.

So why do we tend to catch more colds and flu during the colder months? There are a couple of explanations.

One is that we spend more time indoors, closer to people who might be breathing germs on us. The other: Cold air tends to be drier, and lower humidity helps viruses survive in the air.

“When you’re sick, the micro­scopic droplets of moisture that you exhale contain virus particles,” Schaffner explains. “When the air is dry, the droplets evaporate but the tiny virus particles remain suspended in the air longer and can be breathed in by someone else.” And researchers at Yale University have found that when the temperature inside your nose drops, it ­becomes more hospitable to cold viruses.

That said, staying warm and dry will make you more likely to go outside and get some physical activity. “Even if a virus gives you a cold, moderate exercise will make you feel better and may hasten your recov­ery,” he says.

The trick to being comfortable is to dress in base layers made from moisture-wicking material (such as merino wool, polyester, or silk), add a warm fleece or down layer, and top with a wind- and water-repellent jacket.

Editor's Note: This article also appeared in the February 2017 issue of Consumer Reports on Health.