Conventional wisdom tells us that cold weather—or getting chilled or overheated—can cause a cold. But these conditions alone really don't affect the development of a cold, according to Health Canada.
So, why do most colds occur in the fall and winter, as well as when the seasons are changing? Cold weather tends to force people inside, where it's much easier for germs to spread. Plus, once school starts in August or September, kids are spending more time inside with other kids, where they are more likely to pass germs back and forth.
Also, it's easier for most common cold-causing viruses to survive when humidity is low, such as during the colder months. All that dryness also makes the lining of our nasal passages dryer and more vulnerable to viral infection.