Martin Wattenburg & Fernanda Viegas created the Wind Map as a visual model of the winds blowing over North America at any given time.
Surface wind data comes from the National Digital Forecast Database. These are near-term forecasts, revised once per hour. So what you’re seeing is a living portrait. (See the NDFD site for precise details; our timestamp shows time of download.) And for those of you chasing top wind speed, note that maximum speed may occur over lakes or just offshore.