A yellow Met Office warning for snow and ice has been issued for the whole of Wales.
Temperatures are set to dip and large parts of the country are set to snow falling, with up to 10cm on some of the highest peaks.
The first warning is in place from 8pm on Tuesday until 10am on Wednesday.
This story details where the snow is expected to fall.
Welsh forecaster Derek Brockway said that most of the snow would be on higher ground in Wales.
The Met Office warning says: “Wintry showers are expected to continue through Tuesday night and Wednesday morning leaving surfaces wet and leading to icy stretches developing on untreated surfaces.
“These showers will fall as a mixture of rain, hail and snow at times, the snow mostly over higher ground.
“Some places are likely to see 1-3cm of snow, mainly above 200m, with 4-8cm possible over the higher ground in northwest England, Wales and west Scotland.”
Mr Brockway added that there was also uncertainty about whether there would be more snow – or rain – on Wednesday night with a band of low pressure across the region.
He said: “Uncertainty in the track of low pressure in the south on Wednesday night into Thursday. Threat of rain and some snow! One to watch and keep an eye on.”
Met Office forecast Bonnie Diamond says they are watching what direction the low pressure takes.
“At the moment it looks like it could bring a band of rain that when it goes across south Wales could fall as snow,” she said. “We are tracking it at the moment, as it is one to look out for. At the moment it looks like it is going to clip south Wales.”
She also warned that the working week is going to end with more heavy and persistent rain for areas of Wales that have already been hit badly by Storm Dennis.
“The heavy rain is going to arrive on Friday across Wales and it is not really going to stop until the early hours of Saturday morning,” she says.
There could be between 30 and 50mm of rain between Friday and Saturday.