Cold Weather Myth
The Myth:
Cold weather causes colds, influenza and other illnesses.
The Fact:
Cold weather by itself does not cause any illness. Germs and viruses cause illness. However, when the temperature drops outside, it may affect several factors that can, in turn, increase your chances of getting sick.
The flu is basically a seasonal disease. There's no doubt about it. But it's not because of cold weather, as one might think. The reason the flu is seasonal actually has a lot more to do with sunlight than temperature.
Doctors and researchers have noted time and time again that increased levels of vitamin D seem to help protect already healthy individuals from contracting the flu. Vitamin D has an immensely positive effect on the immune system. So it's no surprise that colds and the flu spread rapidly during winter months, when the sun is less intense and is visible less often: the body is not able to produce as much vitamin D as it can during the summer.