Thats what I've always said.
Try working up in the arctic and see how fast the heat of day vanishes as soon as the sun does. The ONLY thing that can trap a little heat is water vapor, clouds. Otherwise a clear arctic sky means a darned cold night. It's the one place on earth where it seems you can feel directly the coldness of space.
Yep, thats what I have always observed as well. Clear cloudless nights are usually colder, unless local weather has specific conditions which keep it warm, Air inversions for example. Weather is not Climate however, and that is something the Warmers just get their little beans wrapped around.
The water vapor clouds keep things warm at the surface, and at high elevations they are part of the mechanism of Infra Red heat being released into space. Al Gore is... dead wrong, this proves it.
HAPPY DANCE!