However, warnings were issued of rail disruption tomorrow and possible flooding over the weekend.
Forecasters said Christmas Day would be one of the mildest on record, and temperatures may top 14C in the east and north-east of Scotland.
The UK record is 15.6C, set in Leith in 1896, and equalled at Killerton in Devon in 1920.
A total of 28,000 passengers are booked to travel today with train operator East Coast – the largest cross-Border transport firm – many of them travelling to or from Scotland.
Thousands more will head south – or north – by car, coach and plane.
East Coast will have extra staff on duty at stations, with its last pre-Christmas trains leaving Edinburgh and London King’s Cross at 5pm tomorrow.
On the west coast, Virgin Trains declined to give numbers because it is bidding for a new franchise, but it said its services would be “extremely busy”.
Edinburgh airport expects to handle 23,000 departing and arriving passengers today, with 16,000 using Glasgow airport.
A further 14,000 and 8,500 will pass through the two airports respectively tomorrow.
On Christmas Day, 1,000 passengers at Edinburgh and 1,700 at Glasgow will be on flights to and from places such as Dubai, Tenerife and Cape Verde, off the west African coast.
However, the total numbers flying over the festive period is down on previous years. Glasgow said it would handle a total of 135,000 between today and 3 January, compared with 160,000 in 2008. Numbers over the past two years have been reduced by bad weather. However, a spokeswoman for Aberdeen airport said: “We expect this weekend to be one of our busiest. Even on Christmas Day, we have more flights than in previous years.”
The Automobile Association forecast 18 million cars would take to the UK’s roads over the holiday period – more than half of the total registered.
For drivers heading south, roadworks not lifted for Christmas include on a 12-mile section of the M62 near Huddersfield in West Yorkshire, on more than 32 miles of the M1 near Luton in Bedfordshire, and on a 15-mile stretch of the M25 near St Albans in Hertfordshire.
ScotRail passengers face disruption tomorrow because of a signallers’ strike, despite Network Rail insisting last week that the industrial action would not affect services.
Train frequencies will be cut by up to half on the Glasgow to Barrhead, Paisley Canal, Whifflet, Gourock and Cathcart circle lines.
Managers will take over from the strikers, but Network Rail said it had now decided to reduce the number of trains running “to give a little more flexibility so the services we do operate are more robust”.
However, the firm said the three-day strike, over career progression, would not affect trains on Boxing Day, when a reduced service had been due to operate anyway. No trains run on Christmas Day.
A ScotRail spokeswoman said: “This action is beyond the control of ScotRail and we apologise for any inconvenience caused.
“Everyone should check their journey before they set out, in particular noting their last train home.”
The Met Office has issued a yellow – “be aware” – severe weather warning for potential flooding across western Scotland, north of Glasgow, on Christmas Day and Boxing Day. It said: “Persistent and sometimes heavy rain is likely to commence during Christmas Eve. This will continue at times through both Christmas Day and Boxing Day, bringing an increasing risk of localised flooding issues.”
Transport minister Keith Brown warned travellers to be prepared for changes in the weather.
He said: “Christmas is understandably a busy time of year for our roads, railways and airports and we face additional challenges when temperatures drop or heavy rain is forecast.
“These conditions inevitably cause disruption. We’ve coped well so far with what winter has thrown at us, but there is no room for complacency.
“The public play a pivotal role by responding to pleas from the police and Transport Scotland to make effective preparations for travel on the roads.
“I would urge people to follow this advice for their own safety and convenience.”