The UK is set for the its first full taste of wintry weather this week, with the Met Office issuing ice and snow warnings for parts of England, Scotland and Northern Ireland.
Meanwhile, weather forecast service MeteoGroup warned that conditions across the UK and Ireland will turn unsettled over the coming days as a deep area of low pressure forms in the North Atlantic, which will lead to a "powerful" storm.
Looking ahead to the coming week, a spokesman for the Met Office said: "We're expecting the first real cold blast in these parts. We will see snow on the hills, and in the south of England perhaps some sleet and hail."
Scotland will be the worst-affected region, with around 10cm or more of snow expected on the country's mountains. The spokesman commented: "Across the tops of the Scottish mountains it will be pretty horrendous."
According to the Met Office, snow is also expected tomorrow in the north of England and Northern Ireland, and in the northern and western parts of Wales, mainly in the mountains.
In the South West, the moors will experience wintry conditions, while the Midlands may see "a bit of sleet" at the beginning of the week.
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The Met Office spokesman said it was too early to predict a White Christmas.
He added: "It does look as though the unsettled weather theme will continue, but we can't really pin down any detail about the actual weather type on Christmas day itself. At this stage it's still a long way away before we could give precise detail."
The Government-funded Big Energy Saving Network has published advice for the British public to stay warm during the cold snap.
The network, which is made up of the Energy Saving Trust, the Department of Energy and Climate Change and Citizens Advice, recommended the use of insulation on pipes and walls, as well as using draught excluders and radiator reflector panels.
It also stated that using heating controls such as thermostats correctly can save bill payers between £70 and £150 a year.
The Big Energy Saving Network advised that thermostats should be set to the lowest comfortable temperature, which is typically between 18C and 21C, and added that the thermostat does not need to be turned up when it is colder outside; the house will heat up to the set temperature whatever the weather, although it may take a little longer to do so on colder days.
The organisation also advised setting a timer on the central heating so that it comes on half an hour before people get up, and switches off half an hour before they go to bed.
The group pointed out that setting the heating to come on at certain times can help to prevent pipes from bursting.
The network commented: "As the temperature begins to drop, it's important that we are aware of the best ways to stay warm this winter.
"By following these simple steps you can stay comfortable and save money on your energy bills."
RAC spokesman Simon Williams said: "Colder, more wintry weather coincides with an increase in call-outs for us, so it's worth drivers taking some simple steps to avoid an unfortunate breakdown.
"Coolant, antifreeze and oil levels should all be checked, as should the state of tyres and quantity and concentration of screen wash.
"Starting problems are exacerbated in cold weather, and this might signal a faulty battery, so this is also something worth thinking about.
"When planning your journey make sure you have some essential supplies with you - food and a hot drink for you and your passengers, as well as spare blankets, a torch, a shovel for snow and, of course, a charged-up mobile phone.
"That way you can stay safe and be confident you're ready whatever the weather."