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January weather

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January is many people's least favourite month. This is true midwinter without the distraction of Christmas to soften it. One expects January to be miserable and grey and in general it does not disappoint. But generally speaking the month offers at least one period of stable, sunny weather, as high pressure establishes itself, keeping the Atlantic frontal systems at bay.

Sunny intervals

Often the sunny period happens towards the end of the month, as a high pressure zone positions itself over the UK. This happened on 20 January in both 2006 and 2007, replacing wet and windy weather with sunshine. In 2005 there was also sunshine from 21 to 26 January, and even 2004 - an unusually grey January - saw sunshine on 24 to 25 January. In 2014 it was sunny from 19 to 21 January, and in 2017 there were six days of unbroken sunshine from 17 to 22 January as high pressure sat over southern England: fog then set in for three days more, but on the 24th it cleared to give another fine sunny day.

In 2015 after a first half dominated by westerly winds, high pressure started to build from the 17th bringing north-westerly and then northerly winds. But there were in fact regular bursts of sunshine throughout the month, with five days of full sun and twelve at least half sunny. Temperatures sometimes nudged up to ten degrees in the first half, but were in the 5-7 degree range in the second, with hard frosts overnight.

In 2016 high pressure set in from 11 to 21 January, ending an unbroken run of mild westerlies with strong winds that had dominated since the start of November. The early part of the month had already seen more normal temperatures - 7 to 10 degrees - than the 11-14 degree temperatures seen during December (the warmest December on record), and now the high brought a cold snap with temperatures 4-5 degrees by day and dipping below freezing at night. This checked some of the more exuberant signs of spring - dandelions, daffodils and primroses - that had appeared at the end of December. It was also a much sunnier month than the two preceding, with six days of full sun and six of part sunshine. Westerlies set in again from 22 January onwards.

In 2008, after a dismally wet and windy start to the month which brought flooding to some parts of the country, high pressure edged in to bring mainly sunny weather to the south east from the 24th onwards. In 2012, by contrast, the sunshine came a bit earlier, with two spells, one from the 5th to the 7th, and the other from the 11th to the 17th.

It is possible for January to be almost entirely sunny. In 2003 after a tremendously wet late December which caused the Thames to flood to twice its width at Henley by early January, sunny weather set in from about 4 January, and lasted for the whole rest of the month, with the odd grey days intervening and a brief period of snow mentioned below. 2001, meanwhile, managed the remarkable feat of four successive sunny weekends, the only exception being a grey third Sunday.

But high pressure does not always mean sunshine. In 2013 high pressure dominated throughout the month but brought in mainly grey clouds, while 2010 saw sunshine only in the first four and final two days of the month. Both years also saw significant periods of snow - see below. January 2011 was also a particularly grey month, after an unusually grey December and November. Westerlies were the cause in the first half of the month, but even when the usual high set in from the 18th to the 30th, it still brought mainly cloudy days, being centred somewhat to the west.

In 2017 the fine sunny days from 17-22 January were preceded by five days of bitterly cold weather under northerly winds, as the high edged in from the west: as the high retreated eastwards there were five days of fog and cold grey cloud driven by air blowing up from the continent.

In contrast to all these years 2014 saw no high pressure at all. Intense westerly lows battered the country the whole month, bringing twice the normal rainfall to the south of England and making it the wettest January on record. There were floods in many places, including on the Thames at Marlow, Cookham and Chertsey. But there were reasonable amounts of sunshine between the lows, including five full sun days (three in a row from the 19th to the 21st, as is mentioned above, when a Scandinavian high tried to establish itself and failed) and part sunshine on seven other days. Temperatures also remained around average, which was a welcome change after several cold winters (see below).

Cold and snow

Late January and early February are not surprisingly the most likely times of the year to see snow, but in the 16 years up to February 2007 it tended to be very minor and short-lived. Indeed it was widely believed that due to climate change snowy winters were a thing of the past. For example, there was light snow on 28 January 2004 and in 2005 a high to the west of the UK brought cold north winds and snow flurries to the south east, but it did not settle. 27 January 2006 brought a dusting of snow to Kent, which soon melted in the following day's sun.

30 January 2003 was a bit more serious, with 5cm of snow bringing London to a halt in the rush hour. Some people were stranded in their cars overnight and here was widespread criticism of the region's lack of preparation for weather that would be regarded as commonplace on the continent. The snow only lasted on the ground for 36 hours before melting, however.

24 January 2007 also saw 2cm of snow fall overnight, but it had melted by 11am, but then things moved up a gear. Much more serious snow - 10-12 centimetres - fell on 8 February that year, and did not fully melt for 48 hours. With the exception of a few corners of Kent (see March Weather), the south east had not seen snow like this since February 1991, when almost exactly the same amount of snow fell overnight on 7-8 February.

Worse was to come in the winter of 2008-9, however, and for the next four winters (up to 2012-13). In 2009 there was a dusting of snow on 5 January and the early part of the month saw a continuation of the cold temperatures that had dominated in December 2008, with temperatures of 1 or 2 degrees by day and as low as minus 5 overnight. On 7 January they fell to minus 8 to minus 11, and a couple of days saw hoar frost (frost on every twig and surface). But it was not until 1-2 February that there was proper snowfall, with a Scandinavian high bringing cold air from the continent and later Russia, producing 15cm of snow. This was the worse snow for 18 years, beating the February 2007 snowfall, and the start of a prolonged period of snow disruption across the country.

In the winter of 2009-10 things got worse still. December 2009 saw 10-12cm of snow mid month, and then in January 2010 there was further snow right across the country, the heaviest snowfall in 30 years. Again high pressure - initially to the west of the UK and later centred over Scandinavia - was the culprit. In the south east between 10 and 20 centimetres of snow fell overnight from 5-6 January and on 8 January a satellite picture showed the whole country covered with white. With temperatures as cold as minus five degrees overnight and only 2-3 degrees at best by day in the south east, this snow did not melt, and it was topped up with more snow in Kent over the weekend of 9-10 January, and to the south and west of London on 13 January, before a thaw set in on the 14th.

There was then a hiatus in January 2011, but only after the coldest December in 100 years, which had seen snow on the ground the whole month and sub-zero temperatures. Despite this, neither January or February saw snow that year, and apart from a brief cold snap in the first three days of the month, January temperatures remained between 5 and 8 degrees.

In 2012 it was back to snow in early February, with a Scandinavia high setting in from 28 January 2012 and producing up to 15 centimetres of snow across the south east on 4-5 February. On this occasion there was snow as far as south as the Balearic Islands and Rome. Meanwhile in 2013 after snow flurries in Kent on 12 January, the 14th saw snow all day, though with only about 1cm settling, while on the 18th there was 7cm more, with a similar amount two days later. From 17 to 21 January temperatures did not rise above zero and the snow did not melt till the 26th.

Since then there has been only minor snow in the south east. In 2014 there was none at all, and in 2015 just dustings or sleet showers overnight in the last week of January and the first few days of February, the result of wintry showers coming down the east coast on a northerly wind. The worst of these was on 3 February, when there was over a centimetre of snow overnight. It had all melted by lunchtime, however. On 17 January 2016 there were two to three centimetres of snow overnight but again it quickly melted in the daylight, while on 12-13 January 2017 northerly winds brought snow and sleet, which however only settled to the north of London, in the Chilterns and Kent: this produced a dusting in most places, but there was still a reasonable covering on the North Downs in Kent on 14 January.

Typical temperatures

Temperatures in January typically hover between 6 and 9 degrees in westerly winds, or as low as 2 or 3 degrees by day under high pressure. 2007 was an exception, with temperatures as high as 13 degrees, and regularly in the 8-11 degree range. At night under clear skies or northerly airflows temperatures can get down as minus six or seven degrees in the countryside.

Out of the wind the sun in January can feel surprisingly warm – by mid month, it has lost its midwinter paleness and starts to pack more of a punch. The author has sat outside a pub eating lunch on the second weekend of the month, and walked in shirtsleeves on the fourth. As the month progresses, the midday sun is noticeably higher in the sky and no longer seems to lurk at treetop level all day.

A curious fact about January is that the mornings are actually at their darkest in the first few days of the month, while dusk is already getting noticeably later. An explanation why this is so can be found towards the end of the December weather page. Sunrise is at 8.06am from the 1st to the 4th of the month, and for the next eleven days edges back only very slowly, reaching 8am on 15 January. It then advances by just over a minute a day, reaching 7.40am by the end of January.

At the other end of the day sunset is already at 4pm at the start of the month, nine minutes later than its mid-December minumum, and has advanced to what seems like a miraculously late 4.48pm by the end of it. The sudden realisation around the middle of the month that it is still daylight at 4.30pm is one of January's minor pleasures. By the end of the month, there is light enough for walking in the countryside until 5.20pm.

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