The Met Office is warning of snow and very low temperatures.
We're being told to be prepared for snow showers and freezing conditions across Wales.
A yellow warning from the Met office is in place til 23:55 tonight, thanks to the weather front moving in from Russia known as the "Beast from the East".
Parts of Swansea and Neath have had a dusting of snow overnight with forecasters warning of the chance of more to come.
The bitter conditions are going to last a few days.
Further yellow 'be aware' warning are in place for snow and ice on Thursday, Friday and Saturday.
This is the latest update from the Met Office for today (Tuesday): "Snow showers or longer periods of snow are expected on Tuesday, accompanied by very low temperatures.
There is the potential for travel delays on roads, with some stranded vehicles and passengers, as well as delays or cancellations to rail and air travel.
Some rural communities could become cut off.
Power cuts may also occur and other services, such as mobile phones, may be affected."