As the Christmas travel rush began winding down, four Aer Lingus flights to Heathrow, two from Dublin and one each from Shannon and Cork, were cancelled last night because of freezing fog in the London area. Two Ryanair flights to Gatwick were also affected by the weather. Ninety flights in all from London airports were affected, writes Tim O'Brien.
It was hoped that passengers on the flights would be accommodated on other aircraft.
However, most seasonal travellers reached their destinations over the weekend, according to the main carriers.
The AA said traffic volumes on all the main routes out of Dublin were much lower than expected yesterday, "indicating that most people have reached their destination by now".
At Dublin airport, airlines have capacity for fewer than 45,000 passengers today, a significant reduction on the numbers that flew in over the weekend, while Cork and Shannon airports are how also expecting relatively quiet days.
A Dublin Airport Authority spokeswoman said Christmas falling on a Tuesday had given travellers the opportunity to take advantage of a few extra days' travel time. Some 230,000 passengers passed through the airport's doors from Friday to Sunday, while ferry companies expected a quiet day today.
Inbound travellers hoping for a white Christmas will most likely be disappointed, however, as Met Éireann said that high levels of sunshine were likely, particularly in the northwest, one of the most likely spots for snow at this time of year.
There will be scattered hail showers, however. In the south and southeast, rain is expected, clearing slowly as today goes on. Frost will form in many areas tonight as cloud breaks and southwest winds ease, while the forecast for Christmas Day is cold and breezy, with bright or sunny spells and scattered showers.
St Stephen's Day will be fairly mild, but with fresh to strong southwest to southerly winds, according to Met Éireann's three-day forecast.
AA Roadwatch said traffic volumes were not expected to be heavy today. Dublin and the regional cities are expected to be busy today, however, as last-minute shoppers get busy.
The AA has warned motorists to be wary of icy patches.
A seasonal warning was also issued by the chief executive of the Road Safety Authority, Noel Brett, who reminded drivers to take special care in wet, foggy or icy conditions, always wear a seat belt, and never drink and drive.
Long-distance Irish Rail passengers should check www.irishrail.ie for details of services in light of industrial difficulties over the introduction of new timetables.
Dublin's Dart service will operate today until 9pm.