Peak flu season generally refers to November to December in winter and January to February in spring. Influenza can occur all year round, but the peak season is in winter and spring, which is November, December or January and February every year. Fall is also the season when influenza is prevalent because the weather is hot and cold, and people are susceptible to cold and have lowered resistance to infection. Most of the incubation period of influenza is 1 to 3 days, and it is prone to respiratory complications and extra-pulmonary complications. So in these months, must pay attention to keep warm, active exercise to enhance resistance, in order to be able to prevent the situation of viral infection, pay attention to personal hygiene, daily living environment to maintain indoor ventilation.