The winter of 2009–10 in the United Kingdom (also called The Big Freeze of 2010 by British and Irish media) was a meteorological event that started on 16 December 2009, as part of the severe winter weather in Europe. January 2010 was provisionally the coldest January since 1987 in the UK. A persistent pattern of cold northerly and easterly winds brought cold, moist air to the United Kingdom with many snow showers, fronts and polar lows bringing snowy weather with it.

The first snow fell on 17 December 2009, before a respite over the Christmas period. The most severe snowy weather began on 5 January in North West England and west Scotland with temperatures hitting a low of in Greater Manchester, England. The snow spread to Southern England on 6 January and by 7 January the United Kingdom was blanketed in snow, which was captured by NASA's Terra satellite. The thaw came a week later, as temperatures started to increase.

The winter weather brought widespread transport disruption, school closures, power failures, postponement of sporting events, and 25 deaths. A low of was recorded in Altnaharra, Scotland on 8 January 2010. Overall it was the coldest winter since 1978–79, with a mean temperature of .

Timeline

December 2009

16 December On 16 December forecasters warned of very heavy snowfall to come. A band of rain moved southwards over the UK, which brought some snow. Snow fell in Kent, Surrey, Sussex and Hampshire, which brought some disruption. Day time temperatures were around and a low of was recorded in Surrey.

17 December On the 17th, easterly winds brought heavier and persistent snow showers to eastern England and Scotland. Heavy snow showers brought accumulation up to in Aberdeenshire, Perth, Kinross and Fife, with some snow showers reaching Glasgow and western parts in the afternoon and evening. In Kent, it caused chaos as motorists on the A21 were stuck for several hours during the evening and night.

18 December

More heavy snow showers followed on the 18th after heavy overnight snow caused widespread disruption across England in the South East, East Anglia, the East Midlands, Yorkshire and the Humber. Easterly winds brought further snowfalls in both the northern and southern halves of the UK.

Overnight, five Eurostar trains were stuck in the Channel Tunnel after cold temperatures caused electrical failures, trapping 2,000 people for 16 hours. Many schools in England were closed. Four Eurostar trains broke down inside the Channel Tunnel, after leaving France, and one in Kent on 18 December. Although the trains had been winterised, the systems had not coped with the conditions. Over 2,000 passengers were stuck inside failed trains inside the tunnel, and over 75,000 had their services disrupted. All Eurostar services were cancelled from Saturday 19 December to Monday 21 December 2009. An independent review, published on 12 February 2010, was critical of the contingency plans in place for assisting passengers stranded by the delays, calling them "insufficient". Snow also disrupted motorways, including the M1, and many airports were closed.

19 December The 19th brought snow to northern areas. The wind changed to a northerly with a front pushing south over Scotland. of snow accumulated in northern Scotland, southern Scotland and parts of north and north-east England.

20 December Overnight, north-westerly winds brought snow showers to western, northern and central Scotland, Northern Ireland, north Wales and northern and western England. Northern and western Scotland had the heaviest snow showers with accumulations up to in places in the morning of snow was lying within Glasgow by 9.00 am. During the afternoon and evening, it snowed heavily again across much of Scotland, Northern Ireland and North Wales, with accumulations up to 10–15 cm (4-6"), causing school closures and travel chaos the next day.

21 December On the 21st some further snow showers affected some parts of the UK with some particularly heavy showers in northern areas.

The M25 motorway and large parts of the M3, M23, M4, M40, M1 and M11 motorways were brought to a standstill until late into the night, and many towns were gridlocked. About 100 people were able to travel from London Victoria station to Ashford International railway station courtesy of a steam train hauled by Tornado. Widespread transportation disruption affected parts of England, Wales, Scotland and Northern Ireland.

22 December Central Scotland, from Argyll through Glasgow to Edinburgh, had very heavy snowfall during the evening, accumulating an additional . On the Isle of Lewis, one man died due to the very cold weather. The temperature dropped to overnight in Dalwhinnie in Cairngorms National Park, Scotland, and it fell to in Edinburgh.

Fresh overnight snowfall brought renewed problems to other parts of the United Kingdom. In England, north Hampshire and the Thames Valley were particularly badly affected. In Basingstoke, some 3,000 motorists were forced to either abandon their vehicles or sleep in them overnight after becoming stuck in gridlocked traffic. 2,000 cars were abandoned. The Manchester area had frozen snow which made some dangerous travelling conditions.

The AA vehicle recovery service accused some local authorities of not acting quickly enough to grit roads and claimed some "key roads" had "not been gritted at all". The Local Government Association dismissed the claims as "unverified, unsubstantiated and unjustified".

23 December In Scotland, overnight temperatures once again dropped to well below freezing, with Dalwhinnie in the central Highlands of Scotland recording a low of and in Edinburgh . Large amounts of snow fell in eastern Scotland, with accumulations of up to a foot recorded in the Lothians, Lanarkshire, Edinburgh, Fife and Perth and Kinross. Serious disruption to road transport lead the Scottish Transport Minister Stewart Stevenson to state that conditions on Scottish roads were the worst for 20 years.

Air travel was disrupted in the United Kingdom, with Southampton Airport cancelling or diverting all inbound and outbound flights until around 11:30AM because of a frozen runway. A Ryanair flight landing at Glasgow Prestwick Airport overshot the runway, though no injuries were reported and the airport was soon reopened. Other public transport was also affected, with train services cancelled for the majority of the day from Southampton Airport Parkway.

Two women were killed and more than 40 people injured following a coach crash on an ungritted country road in Cornwall as a party returned from a trip to see Christmas lights in Mousehole the previous evening. Weather forecasters warned of icy conditions and further snowfall into Christmas Eve, affecting particularly northern England and the East Midlands, which would disrupt those who were planning to travel for the Christmas holidays.

24 December Lying snow gave some travel disruption; however, Christmas Eve was a relatively calm day. However, parts of North Yorkshire, particularly the Harrogate area, experienced heavy snowfall during the day.

25 December On Christmas Day parts of Britain had a White Christmas for the first time since 2004 after snow fell in parts of Scotland, parts of northern and central England and north Wales. Many parts of northwestern Ireland had a white Christmas also, whilst freezing rain affected most other parts of the country.

26 December On Boxing Day drivers in Northern Ireland were warned of icy conditions, but conditions in many other parts of the UK continued to improve as milder air moved in from the south. However, northern England and Scotland remained cold, and night time temperatures continued to drop below freezing. Some Boxing Day sporting fixtures were cancelled or postponed because of continuing icy conditions in places, including the National Hunt meeting at Towcester and all but two of the Scottish Football League's fixtures. Some parts of East Anglia suffered electricity power cuts, including Dedham, Stratford St. Mary and parts of Colchester; in more remote parts of the region, some were continuously without power for 36 hours.

27 December

Parts of England again suffered repeated power cuts, and Scotland experienced fresh snowfall overnight on 26–27 December with the worst affected area being Perthshire, where between fell.

28 December Temperatures fell to in Tyndrum overnight on 27–28 December, and to at Tulloch Bridge in the Highlands. The Met Office issued fresh severe weather warnings and motorists were advised to drive with caution. The A75 between Stranraer and Newton Stewart was closed because of "treacherous icy conditions", while the southbound carriageway of the A9 was blocked between the A8624 and B8081 in Perth and Kinross following an accident at Glen eagles.

29 December Temperatures dropped to in parts of the Highlands overnight on 28–29 December, with Braemar recording Britain's lowest temperature of the winter. Fresh travel warnings were issued on 29 December as the wintry conditions continued to cause problems on Scotland's roads.

The runway of Inverness Airport was briefly closed because of snow and ice, and First ScotRail reduced services to and from Glasgow Central because of the severe conditions.

The snow and icy conditions were good for the Scottish ski industry, which said the weather helped it to experience its best start to the season for several years.

Warnings of heavy snow were issued for Wales, the Midlands, north-west England, eastern and southern England and Yorkshire and Humber. More snow began falling across parts of Wales and central and northern England on the evening of 29 December, with Wales recording the heaviest of the snow showers where some rural areas were cut off by of up to . Snow was also reported in parts of the West Midlands region and Yorkshire.

30 December Sportscotland Avalanche Information Service (SAIS) issued warnings about conditions on Scottish mountains. However, three people died in three large avalanches. Two climbers were killed as a result of an avalanche on Ben Nevis, while a man was airlifted from Liathach, a mountain in Torridon, after getting into trouble, and died in hospital.

31 December Continued icy weather in Scotland on New Year's Eve led to the cancellation of Hogmanay celebrations in Inverness amid concerns over public safety. New Year celebrations in other parts of Scotland went ahead as planned. North-east Scotland experienced fresh snowfall during the afternoon and evening of 31 December. For the second time that week Inverness Airport was closed, forcing several hundred passengers to make alternative arrangements. In Batley, West Yorkshire 2,500 gallons of water leaked into the local gas network, leaving 400 homes in Dewsbury and Batley without gas during sub-zero temperatures. The final homes were reconnected on 7 January. Dublin and most of Leinster in Ireland were hit for the first time in the 2009–10 Winter.

January 2010

1 January Fresh overnight snowfall on New Year's Eve and New Year's Day caused disruption in north-east England, with roads across Northumberland, Tyne and Wear, County Durham, Teesside and the Scottish Borders affected. Snow also fell in parts of eastern Cumbria. In places it was as deep as and motorists were warned not to travel unless their journey was absolutely necessary.

2 January A weather front driven by a strong northerly wind brought heavy snow in north Wales, the Isle of Man and north-west England. Wythenshawe near Manchester Airport had of snow. This affected road transport on 2 January, particularly in the Greater Manchester area with conditions on the M60, M602 and M66 reported to be poor, while Snake Pass, which links Manchester with Sheffield, was closed.