The heatmap shows you the average hourly sales during any day of the week in a single month and tracks it to prior periods. You might use this chart to compare your Thursday's 2-3 PM sales and compare it to prior months. This information is helpful to make sure your are staffing your business most heavily during the hours it is most likely to be busy, and more lightly if the sales have been dropping during certain hourly periods. You might also use this information to decide to run promotions that are valid during hourly periods when your sales are dropping.