In Washington, D.C., flu activity typically rises in October and peaks in winter; U.S. peaks most often fall in December–February, though timing varies. Symptoms often start suddenly and include fever, cough, sore throat, aches and fatigue.
Influenza circulates year-round, and there is no single start date for flu season. Other symptoms include chills, a runny or stuffy nose and headache; some people also have vomiting or diarrhea, which is more common in children. A fever is not required. Flu, colds and COVID-19 can cause similar symptoms, and testing can help identify flu or COVID-19.
