National Solar Radiation Database
The National Solar Radiation Database, or NSRDB, describes the amount of solar energy which is available at any location in the United States. It is generated by the National Renewable Energy Laboratory, with the assistance of many collaborators.[1]
Technical Overview
Per its user's manual, "The NSRDB is a serially complete collection of hourly values of the three most common measurements of solar radiation (global horizontal, direct normal, and diffuse horizontal) over a period of time adequate to establish means and extremes, and at a sufficient number of locations to represent regional solar radiation climates."[2]
There have been two releases of the NSRDB, each covering different time periods.[3] The original covers 1961-1990, while an update covers 1991-2005. The releases are summarized in the following table.
| Original | Update | |
| Years Covered | 1961-1990 | 1991-2005 |
| Measuring Stations |  Total: 237 |
 Total: 1,454 |
| Contents | TMY2 Data Sets | TMY3 Data Sets |
| Documentation | NSRDB User's Manual TMY2 User's Manual |
NSRDB User's Manual TMY3 User's Manual |
| Reference | Program Website[4] | Program Website[5] |