School closures have affected lessons, exams and working parents
Hundreds of schools have reopened after last week's heavy snow to allow pupils to sit GCSE, AS and A-level exams.
Arctic conditions had forced thousands to shut but many are reopening to avoid disrupting tests beginning on Monday. Some are open only for exam students.
Forecasters predict a "slow, erratic climb" out of the freeze. There has been a slight thaw in places but more snow in parts of central England.
Roads managers say milder weather could improve safety, amid salt shortages.
Senior officials on the Civil Contingencies Committee met on Monday to discuss weather-related problems.
Afterwards, the prime minister's spokesman said supplies would soon be bolstered by deliveries from the US and Spain, as promised by Gordon Brown on Saturday.
Transport Minister Sadiq Khan will make a Commons statement on gritting supplies later.
AT THE SCENE
Nick Ravenscroft, BBC News, Runcorn
At this processing plant, the white piles are of salt, not snow. Diggers are perched on top, shovelling furiously. One driver told me it had been non-stop since 0700 GMT. Still the lorries queue along the road.
The company, Ineos, normally supplies salt to industry - for example, to be used in water softeners. But the shortage of the brown rock salt usually spread on roads means desperate councils are seeking alternatives.
Site manager Neil Brow predicts 600 lorries will be filled here this week - not a solution to the UK's road salt shortage, but a help.
The edible salt - it only needs drying to be fit for dinner tables - is mixed with sand to provide traction, then loaded onto gritters for spreading on roads. If the cold snap continues, the company will step up production into next week.
Several councils across the UK have said reserves are almost spent, despite those in England and Wales agreeing to use 25% less per day.
Cheshire chemical company Ineos is supplying dozens of emergency lorry loads of white salt to authorities including Gloucestershire, Bradford and East Riding of Yorkshire.
Tom Foulkes, director general of the Institution of Civil Engineers, said supplies were "running dangerously low".
However, the Highways Agency insists supplies are sufficient to keep main roads open in the coming days.
The agency's David Grunwell told the BBC: "We are hoping that slightly milder conditions over the next few days will give us some respite in respect of salting the roads."
Despite this, Met Office warnings of snow are in place for southern and central Wales as well as south west England.
BBC forecasters say slightly milder air from the east has brought a mix of rain, sleet and some snow across these areas, while up to 10cm (4in) of snow could fall in Yorkshire on Monday.
Philip Eden, vice-president of the Royal Meteorological Society, said: "This is the week things change. It won't be a dramatic sudden change but a long, slow, erratic climb out of the freeze."
A woman has died in the freezing weather in Lanarkshire. Police launched an investigation after she was found partially-clothed outside a church in Carluke.
At least 29 people are thought to have died as a direct result of the cold snap.
Travellers continued to face delays:
- Disruptions are still affecting nine rail operators - including Eurostar - albeit less severely
- Replacement buses are operating on many train routes in Scotland
- British Airways had to cancel some services in and out of Heathrow Airport, while Easyjet axed six Gatwick flights
- Part of the A66 between Cumbria and County Durham was closed because of snow, while the A628 in Derbyshire's Peak District was also shut
- A crash closed part of the A14 near the M1 junction in Northamptonshire and an accident has caused heavy delays on the A1(M) southbound between junctions junctions 48 and 47
Fewer schools are closed than last week, despite fears that treacherous roads would hamper pupils' journeys to sit exams.
In Wales, about 160 schools are shut, in West Yorkshire 94 are closed, while 108 have not opened in Kent after fresh snowfall over the weekend.
However, many insist they will be open for pupils who have to sit GCSE and A-level exams.
Closures in most authorities numbered in the tens, rather than hundreds.
The exams - mostly modular tests for AS and A-levels - will be taken in Wales, England, and Northern Ireland from Monday.
Candidates who cannot sit them might have to wait until the next round in June or have estimated grades - arrangements that exams watchdog Ofqual insists are "the fairest possible".
Scotland, where about 50 schools remain closed, has no exams this month. A spokeswoman for the Scottish government said at least 90% of Scotland's schools were open.
Schools Secretary Ed Balls told BBC Radio 5 live: "Schools should be opening if at all possible. We don't want risk aversion to get in the way of getting the schools open.
"Even if the schools can't open fully, we've been saying to schools for the last few days, open for exams, have the exam centre open."
Council bosses and head teachers have dismissed suggestions they might have closed some schools unnecessarily because of exaggerated safety fears.
Meanwhile, there have been reports of panic buying of food, according to Stephen Alambritis of the Federation of Small Businesses. He said harvesting problems were causing supply shortages and could push up prices.
Sarah Pettitt, who chairs the National Farmers' Union's horticulture and potato board, said growers were struggling to harvest vegetables such as cabbages, cauliflowers and leeks.
"Where we would use a harvester, we are having to throw 100 people at a field to do the job by hand. Then we are having to thaw out the produce in storage."
However, she added that shortages were not imminent.