Two major incidents have been declared and more than 100 people have been rescued as floodwater inundates Lincolnshire and Leicestershire
Yellow warnings for snow and ice are in effect across large parts of the UK as flooding and snow cause delays on the roads and railways and force hundreds of schools to close
Manchester Airport has reopened its runways after they were closed on Monday morning due to "heavy snow", but delays remain
The Environment Agency issues more than 190 flood warnings across England, while the coldest temperature of the UK winter so far, -13.3°C (8F), was recorded overnight in Loch Glascarnoch
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Snow, ice and rain cause disruption in the UK
More snowy pictures, courtesy of the BBC Weather Watchers:
Image source, Tweedie / BBC Weather WatchersA snowbear in Drumoak, Aberdeenshire
Image source, Olga / BBC Weather WatchersA snowy road in Bettws Gwerfil Goch, Denbighshire
Image source, DarenBob / BBC Weather WatchersA snow covering in Darwen, Lancashire
Delays at all three of Manchester Airport's terminals are likely this morning as a result of the 45-minute runway closure earlier this morning.
But according to Flightradar24, only three flights leaving Manchester have been cancelled - to Abu Dhabi, Zurich and Copenhagen.
Thirty-five departures and 27 arrivals have been delayed. The airport is covered by two weather warnings - one for heavy rain until 08:00 GMT and another for snow and ice until midday.
Further to that news on the M25 and M5 closures, National Highways says a number of A-roads across England are also closed because of snow, flooding or crashes.
They include:
The M5 has been closed southbound between Junction 11a at Gloucester and Junction 12 at Quedgeley due to extensive flooding following heavy rain.
National Highways says traffic officers are assisting with police at the scene.
We've reported delays on the railways and in the air - meanwhile, thousands of journeys on the M25 in Surrey are being delayed, as the motorway is closed anti-clockwise from junction 10 for the A3 to junction 8 for Reigate.
Just after midnight National Highways said a lorry "struck the central reservation and came to rest sideways across the carriageway".
The road surface is now being "assessed by a specialist engineer for damages". Diversions are in place via local A-roads
Some good news for passengers travelling through Manchester Airport - teams have been able to clear the runways and both have been reopened in the last few minutes.
But in an update at 07:15 GMT Manchester Airport warns that "some departures and arrivals may still experience delays".
Posting on X the airport adds: "Please check with your airline for the latest flight information and allow extra time for your journey today.
"We would like to thank our teams for their hard work in getting the runways operational again."
We have been monitoring the disruption on the rail networks - let's bring you the latest:
As we've reported, the Environment Agency has issued flood warnings across England - the number has recently increased from 139 to 146.
They reach from Yorkshire to south-west England, as the image below shows.
There are another 288 "flood alerts", which are less severe, and mean flooding is "possible".
Image source, Environment AgencyThis image from the Environment Agency at 07:15 GMT shows flood warnings across England
More details from Manchester Airport, where runways are closed - a number of flights due to arrive have either had to delay their take-off time, or are in holding patterns.
According to flight-tracking website Flightradar24, an easyJet flight from Hurghada was the last plane to land at 05:30 GMT at Manchester before the runways were closed - it was supposed to land just after 02:00.
One Qatar Airways flight from Doha appears to have been diverted to Birmingham - yesterday more than a dozen were diverted to Heathrow, Gatwick, Dublin, Glasgow and even as far as Paris.
There are more delays on Manchester Airport's departure board - so far only two flights have been cancelled, according to Flightradar24.
Image source, ReutersSnow ploughs and tractors worked for hours on Sunday to try to clear Manchester Airport's tarmac and runways
Simon King
BBC weather presenter and meteorologist
It’s a very complex and dynamic weather situation this morning.
The amber warning has now expired across northern England but the impacts of severe weather are likely to continue for most of the morning.
With fresh snow falling overnight in Wales, the Midlands, northern England and into parts of Scotland, there will be some very difficult conditions on roads with travel disruption continuing through this morning.
Meanwhile, across the south and east Midlands, eastern England and south-east England, heavy rain will continue to clear to the east.
Localised flooding with lots of surface water spray on the roads.
Things should get a little better as the day goes on as the mix of snow and rain clears to the east but further localised wintry showers will continue in parts of Wales, northern England and northern Scotland.
Over the weekend we had a flurry of pictures from our BBC Weather Watchers - and we have had more sent to us this morning:
Image source, Tyke / BBC WEATHER WATCHERSUp in the small Aberdeenshire village of Auchleven, Weather Watcher Tyke has woken up to heavy snow
Image source, Nathan VG/BBC WEATHER WATCHERSNathan from High Leah, Cheshire, sent this image of a Glasgow to London Victoria bus pulling in to pick up passengers amid heavy snowfall
Image source, Daniel / BBC Weather WatchersCars along a road in County Durham are parked and blanketed by snow
Image source, Ann 97 / BBC Weather WatchersOver in Wrexham sleet showers covered the town centre - temperatures there are not expected to rise above 2°C (35.6°F)
In the past few moments, Manchester Airport says it has closed both its runways due to "heavy snow".
Posting on X, the airport says teams "are working to clear the snow as quickly as possible".
Yesterday Manchester had to close both runways for several hours which resulted in delays, cancellations and diversions.
As rush hour approaches in the East Midlands, National Rail is warning that flooding on the railway between Derby and Long Eaton is blocking all lines towards Nottingham.
Services might be cancelled, delayed or revised, National Rail says adding that the disruption is "expected until further notice".
As we reported earlier, poor weather could impact many operators today, including Northern, Great Western Railway, ScotRail and TransPennine Express.
Airports and airlines are continually updating advice for travellers on their websites, based on the latest forecast. Here are some updates from airports across the UK:
Leeds Bradford airport says disruption is likely to extend into today's flight schedule, and customers are advised to check with their airline before heading to the airport.
Liverpool John Lennon airport reopened its runway on Sunday after an earlier closure. Flights are now operating again, however the bad weather has subsequently caused a number of delays and cancellations.
Birmingham airport said on Sunday that its schedule remained business as usual and advised passengers travelling to the airport to allow plenty of time.
And Newcastle airport said snowy conditions were lifting on Sunday and the runway was fully cleared. It said it was working with airline partners to return its flight schedule to normal.
Image source, PA MediaA train on the Hunt's Cross line in Liverpool on Sunday
National Rail is asking customers to check before travelling, as various routes in England, Scotland and Wales are affected by the poor weather.
Some operators are still impacted by incidents from previous weather issues from last week, it says.
While these operators are not impacted by the weather at present, it advises to check services which could later be impacted on GWR services, external, ScotRail services, external, TransPennine Express service, external and Northern services, external.
"Ice and snow can mean speed restrictions and line closures are implemented to ensure trains are able to run safely on the railway. In very cold weather, snow and ice can build up on the tracks blocking points, the equipment that allows trains to move between tracks," the agency says.
It advises passengers to check their journeys using its real-time Journey Planner, external.
Image source, BBC Weather Watchers/Bettys Hot SpotMore than 100 flood warnings, external have been issued across parts of England, meaning flooding is "expected".
There are also more than 260 flood alerts, external in several areas of England and Wales, meaning flooding is "possible".
This is due to heavy rain and melting snow. Some properties may flood and there may be travel disruption, according to government advice.
The Environment Agency said it is monitoring swollen rivers around the UK as some are near to bursting their banks.
Temperatures will remain below average on Monday, with widespread frost and the threat of ice at times, says the Met Office.
Some rural communities could be cut off by snow, with travel delays and power cuts likely in northern England - up to 15cm more snow could fall in those areas, it adds.
The Met Office weather warnings in place are:
For context: Amber warnings are more serious than yellow warnings and indicate a possible risk to life, as well as more significant travel disruption.
Emily McGarvey
Live page editor
Image source, PA MediaWe're resuming our live coverage after heavy snow and icy rain caused extensive travel disruption across parts of the UK over the weekend.
More disruption is likely today with snow showers, ice and rain to hit parts of the country - and amber and yellow weather warnings are still in place.
Expect flooding from heavy rain and thawing snow, says the Met Office. The Environment Agency has issued more than 100 flood warnings and more than 250 flood alerts.
Some major airports were forced to shut their runways for several hours on Sunday, and rail operators said poor weather was affecting train services with delays and cancellations. There has been extensive disruption on the roads too.
We'll bring you updates on the latest forecast along with road, rail and air travel disruptions throughout today. Stay with us.
Adam Goldsmith
Live reporter
Image source, Getty ImagesIf you were trying to travel early this morning, today has likely been a day of disruption after heavy snowfall hit much of the UK overnight.
The icy front was particularly heavy in the north, where major airports were forced to shut their runways, and a severe weather alert has been in place on roads for much of the day.
As the day went on, infrastructure began to fare a little better, with Manchester and Liverpool John Lennon Airport both reopening their runways after early morning closures. They warn passengers may still experience delays.
And, some were even able to embrace the wintry conditions - we’ve thoroughly enjoyed living vicariously through your sledding videos and dog pictures from here in the BBC basement.
But, as snowfall becomes rain and snow on the ground begins to melt, flood warnings are cropping up, external in the south of the UK - 23 are currently in place alongside a further 226 flood alerts.
This has already caused delays on the railways, where flooded tracks are forcing trains to go slower.
The snow and frost isn't completely gone though - five snow and ice warnings will still be in place across the north of England, Scotland and Northern Ireland in the morning, where residents should expect an icy start.
We’re about to wrap up our live coverage for the evening, but for more on what to expect into the night and tomorrow, you can get the latest updates here.
Thanks for joining us - keep warm and dry.
Image source, EPAAs we reported earlier, there are still several weather warnings in place in the UK.
A number of yellow alerts have also been issued for Monday, here's the list:
For more on what you can expect weather-wise heading into next week, check out the latest forecast from BBC Weather.