The Historical surface weather observation database (HSWOD) is a digital dataset archived by the National Climatic Data center (NCDC). This database has been developed by the Air Force Combat Climatology Center in Asheville, NC and serves as a replacement for the DATSAV3 formatted DSI-9956 (C00442). This new database is a CSV formatted database that is easily viewed in spreadsheets and is easily ... integrated into the Integrated Surface Daily (ISD) dataset. As of this writing (October 2007) the plan is to overlap the two databases (DATSAV3 and HSWOD) through the end of 2007. At that time (January 2008) DATSAV3 will no longer be active and the HSWOD will be fully integrated into the ISD. The HSWOD contains worldwide observations (synoptic, airways, METAR, synoptic ship) for approximately 13,000 sites. All weather elements transmitted are retained; in some cases computed/derived values are incorporated into the record.