Hi Muhammad,
A SAM weather file contains a single year of data.
There are two types of weather files that SAM can download from the NREL National Solar Radiation Database (NSRDB):
- A typical metorological year (TMY) file contains combines data from different years so that the data represents the "typical" solar resource over a historical period of many years. See the NSRDB website for a description of TMY data: nsrdb.nrel.gov/data-sets/tmy
- A single year file contains data from one year.
If you download a "tmy-2020" file from the NSRDB, it contains data from 1998 - 2020. If you download a "2020" file it contains data from 2020.
The NSRDB does not provide data for the current year. After this year, it will take some time for NSRDB staff to process new data for 2022 and add it to the database.
Best regards,
Paul.