Fresh weather warnings have been issued, with sleet and snow forecast in parts of mid and north Wales.
Warnings are in place for Ceredigion, Conwy, Gwynedd, Denbighshire, Flintshire, Wrexham and Powys.
Up to 2in (5cm) of fresh snowfall was expected in places, with as much as 4in (10cm) on higher ground.
Drivers are being urged to take care because of icy roads, while sporting fixtures have also been hit by the weather.
Monday's Newport Gwent Dragons-Cardiff Blues derby has been postponed due to a frozen pitch, and a new date has yet to be fixed.
The Scarlets-Ospreys Boxing Day derby was postponed and is scheduled to be played at 1610 GMT on Monday.
Monday's scheduled football clash between Bangor City and Prestatyn Town has been postponed until Wednesday, 29 December at 1930 GMT.
Tuesday's clash between FC Barrow and Wrexham has also been postponed due to a frozen pitch.
But Ffos Las Racecourse in Carmarthenshire said overnight rain had helped to melt most of the snow on the course and racing was scheduled for Tuesday.
The Met Office forecast outbreaks of rain or sleet in many parts of Wales on Monday, though snow was more likely on higher ground.
The rain and snow was expected to ease for a time this afternoon.
It was also less cold with a gradual thaw on low ground.
The A4061 Bwlch mountain road was still closed in both directions due to hazardous driving conditions between A4107 (Nantymoel) and the B4223 Pen-Twyn Road (Treorchy).
Burst water mains
The A4061 Rhigos mountain road was also closed because of dangerous conditions between the A4059/A465 (Hirwaun) and Hill Street (Treherbert).
The A542 Horseshoe Pass was closed in both directions due to snow between B5103 (Llangollen) and A5104 (Llandegla).
Meanwhile, Dwr Cymru Welsh Water said it took more than 5,000 calls on Boxing Day about problems to supply - over five times the normal amount.
During the bad weather there have been up to 185 burst water mains a day.
Welsh Water has doubled the number of people on standby to deal with incidents and has added 30 4x4 vehicles to its fleet.
It is also trying to help people avoid frozen pipes by producing a film which can be viewed on its website.
The company advises keeping heating on a constant low temperature during very cold weather.