Temperatures dropped to -9°C in parts of the UK and -6°C in Wales in what has been the coldest night of the year since mid-March and the cold snap is set to continue. Forecaster say that Friday night could be even colder with lows of -7 °C. in parts of Wales.
Parts of the UK could see 5cm of snow on Friday with temperatures expected to drop as low as minus 10°C in some areas.
BBC Wales weather presenter Derek Brockway said on the first day of meteorological winter (December 1): "Temperatures dropped as low as -6°C in places last night."
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A yellow weather warning for snow and ice will remain in place on Friday for the eastern coast of the the UK, stretching from Scotland to East Anglia. Ice warnings remain in place for Northern Ireland and south-west England.
Met Office meteorologist Ellie Glaisyer said the forecast for Friday said: "For most of us it will be dry and bright. There will be some wintry showers over the hills. There could be 2cm to 5cm of snow for areas 100m to 200m above sea level, with rain falling at lower levels, particularly Northern Ireland and western Scotland.
"The North York Moors and parts of Scotland will likely get snow. There will be another widespread frost, with a max temperature of 5C across the South."
The Met Office forecast for Wales says: "After a frosty start, most of Wales will have a dry day with some winter sunshine once any early freezing fog clears. Wintry showers may clip Anglesey and Pembrokeshire at times. Feeling cold but winds staying very light. Maximum temperature 4°C.
"Temperatures quickly dropping below freezing this evening with a sharp frost developing inland. Freezing fog patches forming inland, especially in the east. Wintry showers arriving on many other western coasts."
Forecast maps are showing that it will feel like -4°C at 10am in Cardiff on Friday morning, and like 3°C in Swansea at 2pm on Friday afternoon. It will be another cold night tonight with lows of -7 °C.
The Met Office has warned that the dip in temperatures can mean that pipes freeze and thaw again, potentially causing them to burst.
The forecast for the weekend in Wales says: "Freezing fog patches in places at first, perhaps lingering in some eastern locations. Otherwise, sunny spells for some but wintry showers are possible in the west, pushing east later. Cold. Maximum temperature 6 °C."
For those who may be travelling on the roads this weekend, National Network Manager at National Highways, Dale Hipkiss, advised motorists to keep an winter kit in the car while driving.
"Keeping a kit of essential items like a torch and warm clothes, in your vehicle, can be vital in case you and your passengers become stranded," he said.
"Freezing conditions bring so many hazards such as snow and ice, so please … plan ahead for your journey, check weather forecasts, and if weather conditions do become challenging whilst travelling, adjust your driving behaviour and take extra care.
"It's also a good idea for people to check (your) vehicles, such as tyres, coolant and oil levels, etc. before heading out to reduce the risk of breakdowns."
He added: "If you do unfortunately find yourself in an unsafe or vulnerable situation and need assistance, please contact the emergency services."
Moving into next week, the weather is likely to remain cold with a north-easterly air flow pushing through frigid air from the north.
The Met Office predicts a good deal of dry, sunny weather for many, showers remain possible across the UK, particularly in eastern coastal areas.
However, showers could turn wintry at times.
The weather will become increasingly unsettled and less cold in southern and central areas next week, but it will probably remain cold with further coastal wintry showers in the north. The outlook for Sunday to Tuesday in Wales says that it will turn increasingly unsettled in Wales with spells of rain and turning milder by Tuesday.
