The Unofficial PSM3 User’s Guide#

This website is a source of information about data from the Physical Solar Model v3 dataset, part of the National Solar Radiation Database (NSRDB), a free and public irradiance and meteorological database from the National Renewable Energy Laboratory (NREL). However, this project is not directly affiliated with or endorsed by the NSRDB team or NREL. As such, the information here should not be considered official documentation. Rather, it is a user-developed effort to document and demonstrate aspects of the PSM3 dataset and web API that are not necessarily documented anywhere else.


This project is still a work in progress. The current content may be rewritten, reorganized, or generally cleaned up in the future. Additional content may be added. In general, readers are encouraged to verify any claims for themselves.

This website follows an open data-driven approach: all claims are drawn from open and reproducible code-based analysis of data retrieved from the NSRDB. That means that you can verify the claims by running the code yourself. However, it also means that the claims have an unknown shelf life; because the NSRDB can change at any time, so might the results of this website’s analysis. Every webpage has a “last updated” watermark to document the data retrieval and analysis date. Where relevant, every webpage also includes a record of changes to its content.


Free and open-source software is a key enabler of modern scientific computing. This project uses many open-source software packages, including: