
A yellow weather warning for fog is in place for Northern Ireland, with visibility expected to fall below 100 metres in places.
The warning has been in place since 22:00 GMT on Sunday and will last until 10:00 on Monday, with inland areas expected to be most affected.
In the Republic of Ireland, Met Éireann issued a status yellow fog warning for 12 counties from 21:00 (local time) on Sunday until 11:00 on Monday.
It covers all of Connacht - Galway, Leitrim, Mayo, Roscommon and Sligo - along with Cavan, Donegal, Longford, Louth, Meath, Monaghan and Westmeath.
Met Éireann said dense fog could lead to poor visibility and difficult travelling conditions.
The warnings span Monday's morning commute, with drivers potentially facing reduced visibility on affected routes.