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PyNIO ("pie-nee-oh") is a Python module that allows read and/or write access to a variety of scientific data formats popular in climate and weather:

  • NetCDF3 / NetCDF4
  • GRIB1 / GRIB2
  • HDF4
  • HDF-EOS2
  • HDF-EOS5
  • Shapefile

PyNIO has a data model interface that is modeled on the NetCDF data model.

PyNIO is developed by the Computational and Information Systems Lab at the National Center for Atmospheric Research (NCAR).

NCAR is sponsored by the National Science Foundation. Any opinions, findings and conclusions or recommendations expressed in this material do not necessarily reflect the views of the National Science Foundation.


PyNIO can be installed on Linux and MacOS systems via conda:

conda create --name pyn_env --channel conda-forge pynio
source activate pyn_env

Documentation and support

PyNIO is currently documented as part of the PyNGL website.

Bug reports and feature requests

Use the GitHub issue tracker to submit a bug or request.