Just an FYI. True clutch chatter is not heard at idle or when the car in in motion with the clutch fully engaged. Clutch chatter only happens during the moment you start slipping the disk, and ends when the pressure plate is fully engaging the disk. Between these two moments, there is a series of really fast alternations of the disk gripping and slipping. These alternations between grip and slip cause a "chattering" noise. This is most common in puck style disks.
The noise you hear at idle is gear rattle. Gear rattle is the engines torsional vibrations going through the gear train. There is a momentary separation between the meshing gear teeth, and which then results in an impact between the meshing gear teeth.
OP, it sounds to me like you had a defective clutch. I doubt it has anything to do with the weather.