Coronaviruses and the Common Cold
Scientists think coronaviruses cause a large percentage of adult colds. These cold viruses are most active in the winter and early spring. Of the more than 30 kinds of coronaviruses, three or four infect humans.
Other Causes of the Common Cold
About 10% to 15% of adult colds are caused by viruses also responsible for other, more severe respiratory illnesses.
The causes of 20%-30% of adult colds, presumed to be viral, remain unidentified. The same viruses that produce colds in adults appear to cause colds in children. The relative importance of various viruses in children's colds, however, is unclear because it's difficult to isolate the precise cause of symptoms in studies of children with colds.
There is no evidence that you can get a cold from exposure to cold weather or from getting chilled or overheated.