The yellow weather warning for radiation fog today is effective in Northern Ireland, Wales and parts of England until 11am.
"Patchy fog" is expected to reform in place overnight according to the Met Office, with warnings that visibility could fall below 100 metres in place.
As well as this, a Status Yellow rainfall warning has been issued for counties Galway, Mayo, Clare, Cork and Kerry. "Valid from 12:01 Thursday 11-January-2018 until 02:00 Friday 12-January-2018".
"This fog will become more extensive overnight and we are expecting frosts in the morning with temperatures expected to drop to below freezing". Top afternoon temperatures of 3° to 7° are given for the day.
Weather conditions today and through tonight will be ideal for the formation of thick and troublesome "radiation fog", experts say.More news: Assam NRC: Two FIRs lodged against BJP legislator
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Still remaining rather cold with highs of 6C.
The bad weather will continue in to Friday, with strong winds and a spell of heavy rain expected. Afternoon temperatures will range from 5 to 9 degrees Celsius, coldest in the north.
The Met Office stated: "Snow showers will be heaviest and most frequent across western Scotland".
An icy arctic blast is set to batter Britain with snow and gale force winds as temperatures could plummet to -10C in some parts of the UK. Windy and mostly cloudy elsewhere too, with the rain spreading eastwards all the while and with some heavy rain in places by dawn.