Happened to me yesterday, got my base built, and was in my garden putting up my iron bars and while it was raining, I wasn't getting wet at all, and also in the Desert, spent a few hours in a desert hub, never overheated or anything.
Same as my response about overheating/freezing. Seems they removed all the old weather survival type stuff from the game. That whole block in buffs.xml is now commented out and not used.
