Does anybody have any good ideas on editing weather? Say for instance if you have custom data? The best way I know how to do this is to get the TMY3 file, and change the extension to CSV (make sure you get a file from the nearest possible location). The file with the .csv extension can be opened in excel and the many columns are labeled.

SO, you can edit the data, then save the file and change the extension back to .bin.

Then, place the new .bin file into the TMY3 (create it, if its not there) in the weather folder of the equest data.

Now, you can select custom weather in the equest wizards and then navigate to the file to use  your edited data.