Weather Data
============

SAM's performance models (except the :doc:`custom generation profile <../custom-generation/custom_generation>` model) use data from a weather file to represent the renewable resource and ambient weather conditions that affect the system's performance.

For details about weather data in SAM see:

* :doc:`Folders and Libraries <weather_manage_folders>`


* :doc:`Weather Data Elements <weather_data_elements>`


* :doc:`Typical Year and Single Year Data <weather_typical_single>`


* :doc:`Time and Sun Position <weather_time_convention>`


* :doc:`Weather Data and LK <accessing-weather-data-from-lk>`


For a description of SAM's weather file formats:

* :doc:`Weather File Formats <../weather-file-formats/weather_format>`

For instructions to download or use your own weather files see:

* Photovoltaic systems: Location and Resource

* Concentrating solar power systems: Location and Resource

* Wind power: :doc:`Wind Resource <../wind-power/wind_resource>`

* Biopower: :doc:`Ambient Conditions <../biopower/biopower_location_ambient_conditions>`

* Geothermal power: :doc:`Ambient Conditions <../geothermal/geo_ambient_conditions>`

.. note:: For more information about using weather data in SAM including links to online data sources and documents, see the `Weather Data <https://sam.nlr.gov/weather>`__ page on the SAM website.

   For a good discussion of weather data for solar energy modeling, see Sengupta et al., (2017) "Best Practices Handbook for the Collection and Use of Solar Resource Data for Solar Energy Applications: Second Edition" available to download from the `Weather Data Publications <https://sam.nlr.gov/weather-data/weather-data-publications.html>`__ page on the SAM website.