Bundle up or you’ll catch a cold.

Being physically cold isn't what gets you sick; exposure to a cold virus does. There's no evidence that going outside with wet hair when it's freezing will make you sick by itself — provided you avoid hypothermia.

But there are some scientifically sound explanations for why people catch more colds in winter. Because we spend more time in close quarters indoors, it is more likely that we'll cross paths with a cold-causing virus spread from another person during the winter. And for several reasons, we may have a harder time fighting off cold and flu virus particles in winter.

But being cold itself isn't what makes sick, and some argue that cold exposure can actually improve your health.