Hi Magpius. I see you are having some troubles with the weather not showing. Well I see it now:
But I had to specifically copy the weather.png file into the campaign map. Which is weird, because omitting the weather.png should make the game revert back to the stock weather.png file for display.
But it seems it is not doing that for some reason.
I can't reproduce this behaviour with my mod either; it only happens with your mod...
Update: the culprit is your terrain.png. Don't know why (yet). Leave that one out the campaign folder and the weather shows fine. Here is a screenshot without your terrain.png:
