Flights have been cancelled at some of the country's biggest airports as snow and blizzard conditions sweep parts of Britain.
Motorists and ferry passengers are also facing disruption while some schools have been closed due to the bad weather.
Heavy snow was lying across Scotland, Northern Ireland and parts of England on Thursday, but the North East has so far escaped. The Met Office issued a yellow warning for snow for the region earlier this week, however.
At Heathrow Airport, 80 flights were cancelled as a forecast of snow and windy weather is expected to impact on services while four flights were cancelled at Gatwick Airport.
A Heathrow Airport spokesman said: ''The latest forecast is for snow this afternoon, which will reduce the number of aircraft able to take off and land each hour.
"Alongside our airline partners and NATS, we have taken the decision to reduce the flight schedule on Thursday to allow airlines to rebook passengers onto un-allocated seats ahead of time where possible.
"We advise passengers to check their flight status with their airline before coming to the airport. We apologise to those whose travel has been affected."
Gatwick Airport advised passengers to check the status of their flight with their airline and apologised for any inconvenience.
A spokeswoman said: "As a result of the forecast of snow and ice today, some route restrictions have been put in place by air traffic control that may cause some delays and cancellations to flights."
British Airways (BA) flights were among those affected at Heathrow.
A BA spokeswoman said: "We're sorry that some of our customers' travel plans have been affected due to the forecast snow at Heathrow, which will lead to a reduction in the number of aircraft which can land or take off from the airport.
"For safety reasons, Heathrow Airport, air traffic control and all airlines have agreed to operate a reduced schedule to help mitigate the effects of the snow which is likely to fall throughout Thursday afternoon and early evening.
"We are refunding or rebooking any affected customers onto alternative flights so they can continue their journeys as soon as possible.
"Customers on some flights can also choose to travel on alternative dates even if their flight is still scheduled to operate."
The airline advised customers to check the BA website for the latest information.
The Met Office has issued yellow "be aware" warnings of wind and snow for Scotland on Thursday, warning of gusts of up to 60mph in places and 4in (10cm) to 8in (20cm) of snow on higher ground.
The warnings also extend to northern parts of England as well as Wales and Northern Ireland, where thick snow blanketed Coleraine and Ballymena.
The weather has affected ferry services, with Caledonian MacBrayne warning of "heavy disruptions".
Northlink ferries and Orkney Ferries also warned disruption was likely due to the weather.
Three schools in Dumfries and Galloway have been closed due to the wintry conditions while seven primary schools and one nursery are shut in the Highlands.
The Met Office described the weather as a "real taste of winter" caused by a polar airmass, which originated over northern Canada, spreading south across the UK.
They said the heaviest and most frequent snow showers are likely across northern and western Scotland, Northern Ireland and around Irish Sea coasts, but eastern coasts will also be affected in the coming days.
Police said there were some minor road accidents in the Highlands while in central Scotland there was a three-vehicle crash at junction 4 on the M77, where no injuries were reported.
The Environment Agency has warned communities on the east coast of England they could face large waves and possible flooding throughout Friday and into Saturday morning.
Lincolnshire, Norfolk, Suffolk and Essex are particularly at risk from the gale force winds combining with high tides to create large waves that could carry dangerous debris including rocks.
The conditions could also lead to traffic disruption and affect coastal properties, the agency said.
People are being urged to take extreme care near the coast and avoid walking along coastal paths and promenades if possible. Motorists should avoid driving through floodwater as just 30cm (1ft) of flowing water can move a car, the agency said.
Mark Sitton-Kent, national duty manager at the Environment Agency, said: "Gale force winds and high tides are likely to create large and dangerous waves along parts of the east coast on Friday and Saturday.
"These conditions could also cause flooding to coastal roads and could impact properties.
"We understand that powerful tides can be dramatic, but please do not put yourself at unnecessary risk by going to the coast for a thrill or to take pictures.
"We are prepared to take action wherever it is needed. We have moved resources and equipment to the coast and the army is on standby to assist if needed."
Environment Agency teams have moved 5,200 metres of temporary barriers and 25 pumps to depots and towns including Newcastle upon Tyne, Blythe, Great Yarmouth, Chelmsford, Rye and Trustthorpe and South Ferriby in Lincolnshire.
The Hull tidal barrier will be operated on Thursday evening, while all east coast flood gates have been closed, the agency said.