Speed and Velocity Conversion. During the summer, I keep a sailboat at Chicago's Monroe Harbor so I watch the weather and winds pretty carefully. There is a NOAA weaher forecast station (CHII2) on the William Dever Crib  which is about 2 miles out in lake Michigan and 2.5 miles east of where I live in Chicago. Historical wind speed data is saved in a file as meters/second.  The conversion factors used on this page are also used on my Marine Forecast page which can be found HERE.