The Met Office has issued a yellow status severe weather warning of freezing fog for Derry.
The warning is valid between 9:00pm on Wednesday and 10:00am on Thursday.
The warning applies to Derry and the rest of the North.
"Patches of fog will form during Wednesday evening across western parts of Northern Ireland, becoming more extensive and locally dense and freezing overnight, then clearing slowly later on Thursday morning.
"The visibility could be less than 100 metres in places," said the Met Office.