In PVSyst versions 6.79 or later, there is now the option to directly import Vaisala's TMY CSV files. GHI and DIF will be imported automatically, along with wind speed and temperature. If you would like to import other parameters from a TMY or use time series data, see the instructions here.

Steps to input the CSV file type into PVSyst:

0. If necessary, download the most recent version of PVSyst (v6.79 or later).

1. Open PVSyst.

2. Click on "Databases".

3. In the "Import Meteo data" section of the screen, click on "Known format".

4. From the drop down menu under "External Data Source", select "Vaisala (Worldwide)".

5. Click on "Choose" to locate the file you wish to import from among your data files.

6. Click on "Import".

7. The file should now be imported correctly, but it's always a good idea to check and view tables or plots of the data when prompted to do so by PVSyst.