DSI-9645 is surface meteorological data. This data set is archived at NCDC, but was created and is maintained by the National Center for Atmospheric Research (NCAR). Most of the data was obtained directly from NCDC and includes data from the World Weather Records publication/data set (DSI-9644). Much data prior to 1951 came from John Wolbach of Harvard College Observatory, who contracted to have ... this data keyed at NCDC. Sharon Nicholson of Florida State University provided African precipitation data. Dennis Shea of NCAR has provided data obtained directly from various countries. Data are from stations around the world. The earliest is from the year 1731. This is an ongoing data set; new data is constantly added. But generally, the newest data is about 5 years old. Major parameters are sea level and station pressure, temperature, and precipitation. After 1960, percent sunshine and relative humidity (or vapor pressure) were added.