Confirmed cases and deaths are counts of individuals whose coronavirus infections were confirmed by a molecular laboratory test. Governments often revise data or report a single-day large increase in cases or deaths from unspecified days without historical revisions, which can cause an irregular pattern in the daily reported figures. Confirmed case and death data are gathered by The New York Times, which sources its data from states, counties, and regional health departments.

The dew point temperature is the maximum temperature at which water droplets can condense and dew can begin to form. Temperature readings are from the Global Surface Summary of the Day provided by the National Centers for Environmental Information.