Dampness in the Carpeting
 

I've noticed that the carpeting on the passenger side is feeling a little damp. It's not wet, just slightly damp. And I also see condensation on the inside of the windows on colder days, telling me that the humidity inside the car is elevated.

Any thoughts where this might be coming from? What should I look for?

One or more of your drains are plugged. Do a search, common problem..............

Agreed, in my case this came from tear in back right drain tray under rear roof that had ripped. Top still unwound, but there was a rip and leak. Water can leak via rip or clogged drains. Do not ignore, take action to reduce water inflow. It often comes behind the vertical rear wall and runs down into the carpet. If you feel below the carpet on the passenger floorboard you might find the result. Do not ignore. I bought new part but others have repaired the drain tray.