Big freeze could hit road and rail.
Freezing weather is taking its icy grip on South Wales this week, leaving commuters bracing themselves for further delays.
Last week's gales are giving way to more settled but much colder weather throughout this week, which could have an impact on roads and railways.
Forecaster Brendan Jones said higher areas of Wales woke up to snow today while lower areas had frost to contend with as winds changed direction bringing cold air from the North Atlantic.
He said: 'Most people are expected to experience some snow by tomorrow morning.
'There is some really nasty weather making its way from Ireland to South Wales.
'Police have been out because hail has been settling on roads and we have seen some very strong winds around the coast.
'Motorists should not rely on the fact that roads have been gritted and should drive with extreme caution.'
A spokesman for the Highways Agency said: 'We advise drivers to take care as the Met Office forecasts snow and widespread ice affecting roads. The Highways Agency will be treating motorways and major A roads in advance of any bad weather and will continue to do so through the cold spell.
'Drivers should check road conditions before they set out and if they have to travel then be prepared with a winter emergency kit.'
Meteorologist Jeremy Plester said: 'It will feel a lot colder than the ridiculously warm temperatures that we have had in January so far because high pressure will be moving from the Atlantic.
'This will bring sunny, crisp, calmer weather with overnight frost.'
But the freeze is bad news for flowers as confused cherry blossoms and daffodils get the message that spring has not yet arrived.
However, sun worshippers will be cheered up by the fact that the Met Office is predicting 2007 will be the warmest year on record as an El Nino weather system forms in the Pacific, potentially bringing a very hot summer to the UK.