The text file "Wind speed.txt" contains hourly data and associated data-source flag from January 1, 1948, to September 30, 2015. The primary source of the data is the Argonne National Laboratory, Illinois. The first four columns give year, month, day and hour of the observation. Column 5 is the data in miles per hour. Column 6 is the three-digit data-source flag to identify the wind speed data processing and they indicate if the data are original or missing, the method that was used to fill the missing periods, and any other transformations of the data. The data-source flag consist of a three-digit sequence in the form "xyz" that describe the origin and transformations of the data values. The user of the data should consult Over and others (2010) for the detailed documentation of this hourly data-source flag series. Reference Cited: Over, T.M., Price, T.H., and Ishii, A.L., 2010, Development and analysis of a meteorological database, Argonne National Laboratory, Illinois: U.S. Geological Survey Open File Report 2010-1220, 67 p., http://pubs.usgs.gov/of/2010/1220/.