Cold, Flu and Virus Symptoms Typically, the cold and flu season arrives in the United States around October and tends to stay until May, peaking between December and February. Some years are worse than other years, in terms of number of people affected and the severity of the illness. ​Cold vs. Flu, What's the Difference? The common cold and the flu (influenza) often share many of the same symptoms, so it can be difficult to tell them apart. The flu is generally worse than th