Easiest way to work with WETTER 2004:

1.) Unzip the ZIP file to a temporary directory.
2.) Run SETUP.EXE
3.) After installation run SETUPWET.EXE from your WETTER folder once
4.) Start WETTER 2004
5.) Press START FROM LAST DESTINATION - WORLD WEATHER - MOST REALISTIC. If you have not saved a flight file called WETTER before, you must create such a file first (Fly in FS2004, land, save the flight file as WETTER, that's all...)
6.) Choose one of the preset regions (left side).
7.) Let WETTER 2004 create weather. This will only some seconds. Look at the weather reports and print them out, if you like, or have a look at the maps to search for fog, rain or thunderstorm areas.
8.) Exit WETTER
9.) Start FS2004, load the WETTER flight file and off you go!