I grew up in Utah. I always remember my brothers and sister using the expression "up in the night" to indicate that someone was clueless, or operating on a mistaken assumption. It would go something like, "Well if he thinks he can walk in here and talk to people like that, well, he's just up in the night." or, "If she thinks she can run a business that way and be successful, well, she's just up in the night."
I've lived in New York for the last ten years, and now my brother-in-law and sister-in-law (both native New Yorkers) love to poke fun at me for my Utahisms, chief among them, "up in the night". They have even gone so far as to say that I made the expression up myself, or that it is particular to my family.
I desperately need to prove to them that this is a real expression, used by people other than me and my siblings... Sooooo... Any help would be great. If anyone can verify that the expressions is used, if anyone knows anything about where it comes from, where it's used... I would so happy (and vindicated) if I could even get just a little bit of info on this one... Thanks!
If the expression is part of Utahism, then it is not made up by a family or a few individuals. It can not be both. It seems the folks who raise the issue need to make up their mind which.
I've discovered that there is a Utah rock band called Up  in the Night. I suspect a connection to the expression you've cited, and I think your brother/sister-in-law should stop laughing at you.
Peter
Now deeper in square 1. Better if it's Texan or New Zealand or something.
