Twenty-six flights have been cancelled between Ireland and the UK because of heavy fog in Britain.
Eleven flights from London to Dublin and seven from Dublin to London were cancelled.
Flights by Aer Lingus, Cityjet and British Airways are all affected.
London City Airport and Heathrow are affected by the fog.
Three Aer Lingus flights were cancelled - both ways - from Heathrow to Shannon. And one Flybe flight was cancelled, both ways, between Dublin and Southampton.
Dublin Airport is advising anyone who has travel plans to check with their airline for the most up-to-date flight information.
Temperatures are set to drop again in the UK overnight - to below freezing in some parts - and fog will thicken across central and south England, the British Met Office said.