Everyday Health allows users to track the flu by ZIP code throughout the year, states Everyday Health. Users enter their ZIP codes in the appropriate field or use the flu tracker's interactive color-coded national map to start. As of 2015, the website offers countywide, week-by-week flu forecasts covering three-week periods.
To make its flu forecasts, Everyday Health considers information it obtains from sources that include the Centers for Disease Control and Prevention, local and regional weather stations, the Internet and social media, explains the company's website. The purpose of the flu tracker is to help people take preventive measures against the flu at home and during travel throughout the nation.