But Cardiff Airport said it was “not expecting any operational disruption” with flights to and from the airport continuing as normal.
The second highest level of warning issued by the Met Office is in place until midday on Sunday, with all counties affected apart from Anglesey.
There is also a yellow snow and ice warning for Wales on Sunday.
Chris Carnell, from Caerphilly, said the road between Pennar Lane, Newbridge, and Coed Duon View, Pentwynmawr was closed on Saturday night because of a bus crash. A photo showed a bus skewed across the snowy road, blocking it.
Gwent Police posted on Facebook , externalthat there were diversions on that road.