TMY2 weather files for 239 U.S. locations can be downloaded free of charge from from the U.S. National Renewable Energy Laboratory (NREL). The TMY2 data are derived from the 1961-1990 National Solar Radiation Data Base (NSRDB). As TMY2 data are based on more recent and accurate data and will make possible more accurate performance and economic analyses of energy systems, these data sets are recommended by NREL for use in place of earlier TMY data sets derived from the 1952-1975 SOLMET/ERSATZ data base. TMY and TMY2 data sets cannot be used interchangeably because of differences in time (solar versus local), formats, elements, and units. The TMY2 data sets and manual were produced by the National Renewable Energy Laboratory's (NREL's) Analytic Studies Division under the Resource Assessment Program, which is funded and monitored by the U.S. Department of Energy's Office of Solar Energy Conversion.
Unlike TMY data, TRNSYS reads unmodified TMY2 data files. Click on the link below to go to NREL's weather data resource website.
Go to NREL's TMY3 Weather Data Site
We have developed a simple Excel macro that allows you to read the
data available in a TMY2 weather data file into Excel. Download the
following file to your computer. When opening it, enable macros and
follow the instructions in the file.
If you wish to put your own data into TMY2 format, first create the columns of data from the previous section with the [xls file]. After the data is in the column format, run the macro, [xla macro file], to compress into TMY2 format. The macro does not add the name place, latitude and longitude at the top of the .txt file; these need to be entered separately.
Reference: (University of the Highlands and Islands, Scotland, UK)