The Map Controller shows the annual mean wind speed at your selected hub height. Since the numbers shown are averages, they combine both windy and non-windy periods. As a rough estimate, an annual mean wind speed of 4.5 m/s (10 mph) is usually considered the cut-off for a grid-connected residential system to be economically viable.

The color overlay on the map allows you to compare different regions using the color scale located on the left side of the Annual Mean Wind Speed tool. "Warm" colors like brown and orange indicate higher wind speeds. "Cool" colors like purple and blue indicate lower wind speeds. You can select different overlays based on the particular hub height you are interested in: 20 meters, 50 meters, and 80 meters.