Changing Climates with a CIV5Climates.xml

[Lucozade33]

Hey all! I was wondering if anyone has had any experience with this file? What exatly does it do? I tried following the pattern here to add a new climate...but it to no avail (yes, I checked the references in the game text and stuff.)
I'm not too sure what it defines considering that there doesn't seem to be a CLIMATE option at all in the game, just TEMPERATURE and RAINFALL stuff...
Help from someone smarter than I, plz?

Thanks in advance. It's in the xml\gameinfo folder btw.