Yea not sure whats going on there with the heat. but it could be something to do with thermal expansion. Once the metal or plastic or whatever gets hot it slightly expands which could give less room for the window to go up all the way. could also be that the weather stripping gets more sticky as heat rises which could also cause the window to not go up all the way.

I havent tested this but there might be some sort of safety feature on the windows that will make it stop if a hand or an object gets in the way of the window closing.. stops before it crushes your hand if a feature like that is there. that could easily be the reason why it mostly happens when its hot. either way a reset would help.

let us know if any of you find the cause to this.

 

Thermal expansion is what i figured as mine would do it also when it got 100+ outside. After it cooled a bit it was ok. I cant say why it would have all of a sudden developed this problem as i have had it for about 3 years and it just started doing this for seemingly no reason. The window reset fixed it. Oh yeah not long after that started happening the window would get stuck down. I cleaned the motor with contact cleaner using the DIY and that problem has seemed to gone away.

 

My passenger window would not work at all. I used the DIY in here to remove the window motor and clean the brushes. This got the window working, but then I ran into the same problem you're having.
I decided to reset the window motor by removing the 3 bolts holding the door panel on. I removed the sticker and followed the reset procedure and it worked like a charm.
Thanks The1Cyrus for that information. I was just heading to pay almost $200for a new motor.
Here is the reset procedure.
http://www.350z-tech.com/zwiki/Servi...eset_Procedure

 

This happened to my passenger window shortly after I got it a few months ago. Go to work, park the car, roll the windows up, and the passenter window would come back down about 3 inches. At first, I was able to just push it up again and it would be fine. Problem would come and go, until finally it just didn't go up anymore. I needed a new motor. It was still covered under warranty, so I got out of a $220 bill at the dealer.