Wikipedia
NetCDF (Network Common Data Form) is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research (UCAR). They are also the chief source of netCDF software, standards development, updates, etc. The format is an open standard. NetCDF Classic and 64-bit Offset Format are an international standard of the Open Geospatial Consortium.
The project started in 1989 and is still actively supported by UCAR. Version 3.x (released in 1997) is still widely used across the world and maintained by UCAR (last update 2012). Version 4.0 (released in 2008) allows the use of the HDF5 data file format. Version 4.1 (2010) adds support for C and Fortran client access to specified subsets of remote data via OPeNDAP. Both Version 3 and Version 4 are planned to be updated by UCAR.
The format was originally based on the conceptual model of the Common Data Format developed by NASA, but has since diverged and is not compatible with it.