Dade,
That map relies on self reporting, and so it does not show accurate numbers of flu in any area. Here's an interesting animated map by the CDC: https://www.cdc.gov/flu/weekly/usmap.htm that shows the progression of flu. If you want actual numbers by week, go here: https://www.cdc.gov/flu/weekly/index.htm. Flu is measured weekly beginning 1 October. This data comes from clinician reports all across the country. For example, I report every case of flu diagnosed in my hospital or in any of our outlying clinics to the Arizona Department of Health Services, who in turn reports the entire state's data to the CDC. Even though we report exact data, the number of actual flu cases is probably about 4 times the reported number, as not every patient goes to the doctor with flu.
