Climate of the United Kingdom

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The climate of the United Kingdom is classified as a mid-latitude oceanic climate (Koppen climate classification Cfb), with warm summers, cool winters and plentiful precipitation throughout the year. The principal factors that influence the country's climate include its northerly latitude (which ranges from 50° to 60° N), the close proximity to the Atlantic Ocean, and the warming of the surrounding waters by the Gulf Stream. The weather can be notoriously changeable from one day to the next but temperature variations throughout the year are relatively small.

The boundary of convergence between the warm tropical air and the cold polar air lies over the United Kingdom. In this area, the large temperature variation creates instability and this is a major factor that influences the notoriously changeable and often unsettled weather the country experiences, where many types of weather can be experienced in a single day.

Contents 1 Seasons 1.1 Winter 1.2 Spring 1.3 Summer 1.4 Autumn 2 Regions 2.1 England 2.2 Wales 2.3 Northern Ireland 2.4 Scotland 3 Sunshine and cloud 4 The Atlantic Ocean 5 Winds 6 Rainfall 7 Temperature 8 Severe weather 9 Climate history 10 See also 11 References 12 External links

[edit] Seasons

[edit] Winter

Winter in the UK is defined as lasting from December to February. The season is generally cool, wet and windy. Temperatures at night rarely drop below −10 °C (14 °F) and in the day rarely rise above 15 °C (59 °F). Precipitation is plentiful throughout the season, though snow is relatively infrequent despite the country's high latitude.

Towards the later part of the season the weather usually stabilises with less wind, less precipitation and lower temperatures. This change is particularly pronounced near the coasts mainly due to the fact that the Atlantic ocean is often at its coldest during this time after being cooled throughout the autumn and the winter. The early part of winter however is often unsettled and stormy; often the wettest and windiest time of the year.

Snow falls intermittently and mainly affects northern and eastern areas, Wales and chiefly higher ground, especially the mountains of Scotland where the amount of lying snow may be significant enough on occasions to permit skiing at one of the five Scottish ski resorts. Snow however rarely lasts more than a week in most of these areas as the cold air brought by northerly or easterly winds, or in a high pressure system gives way to mild southerly or westerly winds introduced by low pressure systems. However, on rare occasions some potent depressions may move in from the north in the form of 'Polar Lows', introducing heavy snow and often blizzard-like conditions to parts of the United Kingdom, particularly Scotland. During periods of light winds and high pressure frost and fog can become a problem and can pose a major hazard for drivers on the roads.

Mean winter temperatures in the UK are most influenced by proximity to the sea. The coldest areas are the mountains of Wales and northern England, and inland areas of Scotland, averaging −3.6 °C (25.5 °F) to 2.3 °C (36.1 °F).^[1] Coastal areas, particularly those in the south and west, experience the mildest winters, on average 5 °C (41 °F) to 8.7 °C (47.7 °F).^[1] Hardiness zones in the UK are quite high, ranging from zone 7 in the Scottish Highlands, the Pennines and Snowdonia, to zone 10 on the Isles of Scilly. Most of the UK lies in zones 8 or 9.^[2] In zone 7, the average lowest temperature each year is between −17.7 °C (0.1 °F) and −12.3 °C (9.9 °F), and in zone 10, this figure is between −1.1 °C (30.0 °F) and 4.4 °C (39.9 °F).^[3]

[edit] Spring

Spring is the period from March to May. Spring is generally a calm, cool and dry season, particularly because the Atlantic has lost much of its heat throughout the autumn and winter. However, as the sun rises higher in the sky and the days get longer, temperatures can rise relatively high; thunderstorms and heavy showers can develop on occasion.

There is a fair chance of snow earlier in the season when temperatures are colder. Some of the country's heaviest snowfalls of recent years have happened in the first half of March and snow showers can occur infrequently until mid-April.

Mean temperatures in Spring are markedly influenced by latitude. Most of Scotland and the mountains of Wales and northern England are the coolest areas of the UK, with average temperatures ranging from −0.6 °C (30.9 °F) to 5.8 °C (42.4 °F).^[4] The southern half of England experiences the warmest spring temperatures of between 8.8 °C (47.8 °F) and 10.3 °C (50.5 °F).^[4]

[edit] Summer

Summer lasts from June to August. Summer can often be a dry season, but rainfall totals can have a wide local variation due to localised thunderstorms. These thunderstorms mainly occur in southern, eastern, and central England and are less frequent and severe in the north and west. North Atlantic depressions are not as frequent or severe in summer but increase both in severity and frequency towards the end of the season. Summer often sees high pressure systems from the Azores dominate.

Climatic differences at this time of year are more influenced by latitude and temperatures are highest in southern and central areas and lowest in the north. Generally, summer temperatures rarely go above 30 °C (86 °F). Scotland and northern England have the coolest summers (average 12.2 °C (54.0 °F) to 14.8 °C (58.6 °F)), while Wales and the south-west of England have warmer summers (14.9 °C (58.8 °F) to 15.4 °C (59.7 °F)) and the south and south-east of England have the warmest summers (15.5 °C (59.9 °F) to 17.7 °C (63.9 °F)).^[5] The record maximum is 38.5 °C (101.3 °F) recorded in Kent in August 2003^[6]—due to its proximity to the European land mass, the south-east usually experiences the highest summer temperatures in the United Kingdom.

[edit] Autumn

Autumn in the United Kingdom lasts from September to November. The season is notorious for being unsettled—as cool polar air moves southwards following the sun, it meets the warm air of the tropics and produces an area of great disturbance along which the country lies. This combined with the warm ocean due to heating throughout the spring and summer, produces the unsettled weather of autumn. In addition, when the air is particularly cold temperatures on land may be colder than the ocean, resulting in significant amounts of condensation and clouds which bring rain to the country.

Atlantic depressions during this time can become intense and sustained winds of hurricane force (greater than 119 kilometres per hour (74 mph)) can be recorded. Western areas, being closest to the Atlantic, experience these severe conditions to a significantly greater extent than eastern areas. As such, autumn, particularly the latter part, is often the stormiest time of the year. One particularly intense depression was the Great Storm of 1987.

However, the United Kingdom often experiences an 'Indian Summer', where temperatures particularly by night can be very mild and rarely fall below 10 °C (50 °F). Such events are aided by the surrounding Atlantic Ocean and seas being at their warmest, keeping the country in warm air, despite the relatively weak sun. Examples of this were in 2005 and 2006, where September, and October even more so, saw above average temperatures which felt more like a continuation of summer than autumn. Autumns since 2000 have been very mild with notable extremes of precipitation; the UK has seen some of its wettest and driest autumns since the millennium.

Coastal areas in the southern half of England have on average the warmest autumns, with mean temperatures of 10.7 °C (51.3 °F) to 13.0 °C (55.4 °F).^[7] Mountainous areas of Wales and northern England, and almost all of Scotland, experience mean temperatures between 1.7 °C (35.1 °F) and 7.5 °C (45.5 °F).^[7]

[edit] Regions

Regional climates in the United Kingdom are influenced by the Atlantic Ocean and latitude. Northern Ireland, Wales and western parts of England and Scotland, being closest to the Atlantic, are generally the mildest, wettest and windiest regions of the UK, and temperature ranges here are seldom extreme. Eastern areas are drier, cooler, less windy and also experience the greatest daily and seasonal temperature variations. Northern areas are generally cooler, wetter and have a smaller temperature range than southern areas.

The United Kingdom is mostly under the influence of the maritime tropical air mass from the south-west, but different regions are more susceptible than others when different air masses affect the country:–

• Northern Ireland and the west of Scotland are the most exposed to the maritime polar air mass, which brings cool moist air.
• The east of Scotland and north-east England are more exposed to the continental polar air mass, which brings cold dry air.
• The south and south-east of England are more exposed to the continental tropical air mass, which brings warm, dry air.
• Wales and the south-west of England are the most exposed to the maritime tropical air mass, which brings warm moist air.

[edit] England

England Climate Averages
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average maximum temperature °C (°F)	6.6 (43.9)	6.9 (44.4)	9.3 (48.7)	11.7 (53.1)	15.4 (59.7)	18.1 (64.6)	20.6 (69.1)	20.5 (68.9)	17.5 (63.5)	13.6 (56.5)	9.5 (49.1)	7.4 (45.3)	13.1 (55.6)
Average minimum temperature °C (°F)	1.1 (34.0)	1.0 (33.8)	2.4 (36.3)	3.6 (38.5)	6.3 (43.3)	9.1 (48.4)	11.4 (52.5)	11.2 (52.2)	9.3 (48.7)	6.6 (33.1)	3.5 (38.3)	2.0 (35.6)	5.6 (42.1)
Sunshine hours	50.5	67.7	102.5	145.2	189.9	179.4	192.8	184.1	135.0	101.3	65.2	43.9	1457.4
Rainfall mm (inches)	84.2 (3.3)	60.1 (2.4)	66.5 (2.6)	56.8 (2.2)	55.9 (2.2)	62.9 (2.5)	54.1 (2.1)	66.7 (2.6)	73.3 (2.9)	83.6 (3.3)	83.5 (3.3)	90.4 (3.6)	838.0 (33.0)
Rainfall ≥ 1 mm days	13.4	10.4	12.1	10.1	9.8	9.8	8.5	9.4	10.2	11.8	12.5	13.1	131.2
Source: Met Office[8] (1971–2000 averages)

England has warmer maximum and minimum temperatures throughout the year than the rest of the United Kingdom, but Wales has milder minimums from November to February, and Northern Ireland has warmer maximums from December to February. England is also sunnier than the other constituent countries throughout the year, but unlike Wales, Northern Ireland and Scotland, the sunniest month is July, totalling 192.8 hours.^[8] It rains on less days in every month throughout the year than the rest of the UK, and rainfall totals are less in every month, with the driest month of July averaging 54.1 mm.^[8]

[edit] Wales

Wales Climate Averages
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average maximum temperature °C (°F)	6.5 (43.7)	6.6 (43.9)	8.6 (47.5)	11.0 (51.8)	14.5 (58.1)	16.8 (62.2)	19.1 (66.4)	18.8 (65.8)	16.2 (61.2)	12.8 (55.0)	9.3 (48.7)	7.4 (45.3)	12.3 (54.1)
Average minimum temperature °C (°F)	1.3 (34.3)	1.1 (34.0)	2.4 (36.3)	3.4 (38.1)	6.0 (42.8)	8.6 (47.5)	10.9 (51.6)	10.7 (51.3)	8.8 (47.8)	6.5 (43.7)	3.7 (38.7)	2.2 (36.0)	5.5 (41.9)
Sunshine hours	42.8	63.4	94.2	148.0	186.8	167.0	181.8	168.7	125.8	90.4	54.9	35.4	1359.3
Rainfall mm (inches)	158.4 (6.2)	113.8 (4.5)	118.5 (4.7)	85.7 (3.4)	80.6 (3.2)	86.0 (3.4)	78.3 (3.1)	105.8 (4.2)	123.8 (4.9)	152.9 (6.0)	156.6 (6.2)	173.1 (6.8)	1433.5 (56.4)
Rainfall ≥ 1 mm days	17.4	13.4	15.1	11.7	11.5	11.4	10.3	12.2	13.0	15.8	16.7	17.1	165.5
Source: Met Office[9] (1971–2000 averages)

Wales has warmer temperatures throughout the year than Scotland, and has milder winter minimums than England, but cooler winter maximums than Northern Ireland. Wales is wetter throughout the year than Northern Ireland and England, but has less rainy days than Northern Ireland; meaning that rainfall is more intense. Wales is also drier than Scotland in every month apart from May, June and December, and there are less days with rain than in Scotland. Sunshine totals throughout the year are more than that of Scotland and Northern Ireland, but less than that of neighbouring England. May is the sunniest month, averaging 186.8 hours.^[9]

[edit] Northern Ireland

Main article: Climate of Northern Ireland

Northern Ireland Climate Averages
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average maximum temperature °C (°F)	6.7 (44.1)	7.1 (44.8)	8.9 (48.0)	11.1 (52.0)	14.2 (57.6)	16.5 (61.7)	18.4 (65.1)	18.1 (64.6)	15.7 (60.3)	12.5 (54.5)	9.2 (48.6)	7.5 (45.5)	12.2 (54.0)
Average minimum temperature °C (°F)	1.2 (34.2)	1.2 (34.2)	2.3 (36.1)	3.3 (37.9)	5.6 (42.1)	8.3 (46.9)	10.6 (51.1)	10.2 (50.4)	8.3 (46.9)	6.1 (43.0)	3.1 (37.6)	2.0 (35.6)	5.2 (41.4)
Sunshine hours	41.0	60.1	90.0	140.8	175.9	150.9	139.6	138.0	113.1	85.5	52.8	31.9	1219.7
Rainfall mm (inches)	119.1 (4.7)	86.5 (3.4)	93.4 (3.7)	70.6 (2.8)	68.1 (2.7)	72.1 (2.8)	73.2 (2.9)	90.8 (3.6)	94.4 (3.7)	114.5 (4.5)	110.5 (4.4)	118.5 (4.7)	1111.6 (43.8)
Rainfall ≥ 1 mm days	17.8	14.1	16.4	12.4	12.6	12.4	13.1	13.9	14.4	16.4	16.7	16.9	177.0
Source: Met Office[10] (1971–2000 averages)

Northern Ireland is warmer than Scotland throughout the year. Maximum temperatures are milder than in Wales from December to April, and milder than in England from December to February, but Northern Ireland is cooler during the rest of the year. Sunshine totals in every month are more than those of Scotland, but less than those of the rest of Great Britain. Northern Ireland is drier and has less rainy days than Scotland throughout the year, except in May, when it rains on more days. Northern Ireland is also drier than Wales in every month, yet it rains on more days. The rainiest month is January, when 17.8 days have more than 1 mm of rain on average.^[10]

[edit] Scotland

Main article: Climate of Scotland

Scotland Climate Averages
Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
Average maximum temperature °C (°F)	5.0 (41.0)	5.2 (41.4)	6.9 (44.4)	9.3 (48.7)	12.8 (55.0)	14.9 (58.8)	16.9 (62.4)	16.6 (61.9)	13.9 (57.0)	10.8 (51.4)	7.4 (45.3)	5.7 (42.3)	10.5 (50.9)
Average minimum temperature °C (°F)	-0.2 (31.6)	-0.1 (31.8)	0.9 (33.6)	2.1 (35.8)	4.5 (40.1)	7.2 (45.0)	9.3 (48.7)	9.2 (48.6)	7.2 (45.0)	4.9 (40.8)	2.0 (35.6)	0.5 (32.9)	4.0 (39.2)
Sunshine hours	30.8	58.1	87.6	128.2	173.2	153.2	145.0	137.5	104.4	74.5	43.2	24.7	1160.4
Rainfall mm (inches)	170.5 (6.7)	123.4 (4.9)	138.5 (5.5)	86.2 (3.4)	79.0 (3.1)	85.1 (3.4)	92.1 (3.6)	107.4 (4.2)	139.7 (5.5)	162.6 (6.4)	165.9 (6.5)	169.6 (6.7)	1520.1 (59.8)
Rainfall ≥ 1 mm days	18.6	14.8	17.3	13.0	12.2	12.7	13.3	14.1	15.9	17.7	17.9	18.2	185.8
Source: Met Office[11] (1971–2000 averages)

Scotland has the coolest weather in the United Kingdom throughout the year, with average minimum temperatures in January of −0.2 °C (31.6 °F).^[11] Scotland is also the wettest constituent country in the UK in every month, apart from in May, June and December, when Wales is wetter. The wettest month is January, with 170.5 mm on average.^[11] Scotland is also the cloudiest part of the UK throughout the year, apart from in June and July, when Northern Ireland is.

[edit] Sunshine and cloud

The average total annual sunshine in the United Kingdom is 1339.7 hours, which is just under 30% of the maximum possible.^[12][13] The south coast of England often has the clearest skies because cumulus cloud formation generally takes place over land, and prevailing winds from the south-west keep this cloud from forming overhead. The counties of Dorset, Hampshire, Sussex and Kent have annual average totals of around 1,750 hours of sunshine per year.^[14] Northern, western and mountainous areas are generally the cloudiest areas of the UK, with some mountainous areas receiving less than 1,000 hours of sunshine a year.^[14]

Valley areas such as the South Wales Valleys, due to their north-south orientation, receive less sunshine than lowland areas because the mountains on either side of the valley obscure the sun in the early morning and late evening. This is noticeable in winter where there are only a few hours of sunshine. The mountains of Wales, northern England and Scotland can be especially cloudy with extensive mist and fog. Near the coast, sea fog may develop in the spring and early summer. Radiation fog may develop over inland areas of Great Britain and can persist for hours or even days in the winter and can pose a major hazard for drivers and aircraft.

On occasions blocking anticyclones (high pressure systems) may move over the United Kingdom, which can persist for weeks or even months. The subsided, dry air often results in clear skies and few clouds, bringing frosty nights in winter and hot days in the summer, when some coastal areas can achieve almost maximum possible sunshine for periods of weeks.

Average hours of sunshine in winter range from 38–108 hours in some mountainous areas and western Scotland, up to 217 hours in the south and east of England;^[15] while average hours of sunshine in summer range from 294–420 hours in northern Scotland and Northern Ireland, to 592–726 hours in southern English coastal counties.^[16] The most sunshine recorded in one month was 383.9 hours at Eastbourne (East Sussex) in July 1911.^[14]

[edit] The Atlantic Ocean

One of the greatest influences on the climate of the UK is the Atlantic Ocean and especially the North Atlantic current, which brings warm waters from the Gulf of Mexico to the waters around the country by means of thermohaline circulation. This has a powerful moderating and warming effect on the country's climate—the North Atlantic Drift warms the climate to such a great extent that if the current did not exist then temperatures in winter would be about 10 °C (18 °F) lower than they are today. The current allows England to have vineyards at the same latitude that Canada has polar bears. A good example of the effects of the North Atlantic Drift is Tresco Abbey Gardens, on the Isles of Scilly, 48 kilometres (30 mi) west of Cornwall, where Canary Island date palm trees grow - possibly the nearest of their kind to the Arctic Circle, at 50° latitude north. These warm ocean currents also bring substantial amounts of humidity which contributes to the notoriously wet climate that western parts of the UK experience.

The extent of the Gulf Stream's contribution to the actual temperature differential between North America and western Europe is a matter of dispute.^[17][18] It has been argued that atmospheric waves that bring subtropical air northwards contribute to a much greater extent to the temperature differential than thermohaline circulation.^[17]

[edit] Winds

The high latitude and close proximity to a large ocean to the west means that the United Kingdom experiences strong winds. The prevailing wind is from the south-west, but it may blow from any direction for sustained periods of time. Winds are strongest near westerly facing coasts and exposed headlands.

Gales — which are defined as winds with speeds of 51 to 101 km/h (32 to 63 miles per hour)— are strongly associated with the passage of deep depressions across the country. The Hebrides experience on average 35 days of gale a year (a day where there are gale force winds) while inland areas in England and Wales receive less than 5 days of gale a year.^[14] Areas of high elevation tend to have higher wind speeds than low elevations, and Great Dun Fell in Cumbria (at 857 m (2,812 ft)) averaged 114 days of gale a year during the period 1963 to 1976. The highest gust recorded at a low level was 191 km/h (118 mph) at Gwennap Head in Cornwall on 15 December 1979.^[14]

[edit] Rainfall

Rainfall amounts can vary greatly across the United Kingdom and generally the further west and the higher the elevation, the greater the rainfall. The Lake District is one of the wettest places in the country with an average annual rainfall total that exceeds 2000 mm.^[14] The mountains of Wales, Scotland, the Pennines and the moors of the south-west of England are the wettest parts of the country, and in some of these places as much as 4,577 millimetres (180.2 in) of rain falls annually,^[19] making these locations some of the wettest in Europe. Most rainfall in the United Kingdom comes from North Atlantic depressions which roll into the country throughout the year and are particularly frequent and intense in the autumn and winter. They can on occasions bring prolonged periods of heavy rain, and flooding is quite common.

Parts of England are surprisingly dry, which is contrary to the stereotypical view—London receives less rain annually than Rome, Sydney or New York. In East Anglia it typically rains on about 113 days per year.^[20] Most of the south, south-east and East Anglia receive less than 700 mm of rain per year.^[14] The English counties of Essex and Cambridgeshire are amongst the driest in the UK, with an average annual rainfall of around 600 mm. In some years rainfall totals in Essex can be below 450 mm—less than the average annual rainfall in Jerusalem and Beirut.

Parts of the United Kingdom have had severe drought problems in recent years, particularly in the south-east of England, which experienced the driest period on record in 2006.^[21] Fires broke out in many areas, even across the normally damp higher ground of north-west England and Wales. The landscape in much of England and east Wales became very parched, even near the coast; water restrictions were in place in some areas.

July 2006 was the hottest month on record for the United Kingdom and much of Europe,^[22] however England has had warmer spells of 31 days which did not coincide with a calendar month—in 1976 and 1995. As well as low rainfall, drought problems were made worse by the fact that the driest parts of the England also have the highest population density, and therefore highest water consumption. The drought problems ended in the period from October 2006 to January 2007, which had well above average rainfall.

[edit] Temperature

Generally the United Kingdom has cool to mild winters and warm summers with moderate variation in temperature throughout the year. In England the average annual temperature varies from 8.5 °C (47.3 °F) in the north to 11 °C (52 °F) in the south, but over the higher ground this can be several degrees lower.^[14] This small variation in temperature is to a large extent due to the moderating effect the Atlantic ocean has—water has a much greater specific heat capacity than air and tends to heat and cool slowly throughout the year. This has a warming influence on coastal areas in winter and a cooling influence in summer.

The ocean is at its coldest in February or early March, thus around coastal areas February is often the coldest month, but inland there is little to choose between February and January as the coldest.^[14] Temperatures tend to drop lowest on late winter nights inland, in the presence of high pressure, clear skies, light winds and when there is snow on the ground. On occasions, cold polar or continental air can be drawn in over the United Kingdom to bring very cold weather.

The floors of inland valleys away from warming influence of the sea can be particularly cold as cold, dense air drains into them. A temperature of −26.1 °C (−15.0 °F) was recorded under such conditions at Edgmond in Shropshire on 10 January 1982, the coldest temperature recorded in England and Wales. The following day the coldest maximum temperature in England, at −11.3 °C (11.7 °F), was recorded at the same site.^[14]

On average the warmest winter temperatures occur on the south and west coasts, however, warm temperatures occasionally occur due to a foehn wind warming up downwind after the crossing the mountains. Temperatures in these areas can rise to 15 °C (59 °F) in winter on rare occasions^[23] This is a particularly notable event in northern Scotland, mainly Aberdeenshire, where these high temperatures can occur in midwinter when the sun only reaches about 10° above the horizon.

July is on average the warmest month, and the highest temperatures tend to occur away from the Atlantic in southern, eastern and central England, where summer temperatures can rise above 30 °C (86 °F). It soared to 38.5 °C (101.3 °F) in Kent in the summer of 2003, the highest temperature ever recorded in the United Kingdom.

2006 saw unprecedented warmth, with many more records being broken. While the year started off around average, and even fell well below average in early-March, the period from mid-April onwards saw a lack of any cooler than average weather. Early-May and June saw temperatures 10–12 °C (18–21 °F) above average at times. July was the hottest month on record, with records stretching back hundreds of years; the highest maximum temperature for July was also broken in 2006. September was the warmest September on record and October was one of the warmest on record. November was also extremely mild, making it the warmest Autumn on record by some margin.^[24] May to October was also the warmest consecutive six months on record.^[25]

Absolute temperature ranges
Country	Maximum temperatures			Minimum temperatures
	°C	°F	location and date	°C	°F	location and date
England	38.5	101.3	Brogdale, near Faversham, Kent on 10 August 2003	−26.1	−15	Edgmond, near Newport, Shropshire on 10 January 1982
Wales	35.2	95.4	Hawarden Bridge, Flintshire on 2 August 1990	−23.3	−10	Rhayader, Radnorshire on 21 January 1940
Scotland	32.9	91.2	Greycrook, Scottish Borders on 9 August 2003	−27.2	−17	Braemar, Aberdeenshire on 11 February 1895 and 10 January 1982 Altnaharra, Sutherland on 30 December 1995
Northern Ireland	30.8	87.4	Knockarevan, near Belleek, County Fermanagh on 30 June 1976 Belfast on 12 July 1983	−17.5	0	Magherally, near Banbridge, County Down on 1 January 1979

[edit] Severe weather

While the United Kingdom is not particularly noted for extreme weather, it does occur, and conditions have been known to reach extreme levels on occasions. In the winter of 1982, for a few days parts of central and southern England experienced temperatures lower than central Europe and Moscow. In contrast, the summers of 1975 and 1976 experienced temperatures as high as 35 °C (95 °F). It was so dry the country suffered drought and water shortages.^[26]

Extended periods of extreme weather, such as the drought of 1975–1976 and the very cold winters of 1962–1963, 1978–79 and 1981–1982, are often caused by blocking anti-cyclones which can persist several days or even weeks. In winter they can bring long periods of cold dry weather and in summer long periods of hot dry weather.

There have also been occurrences of severe flash floods caused by intense rainfall, the most severe was the Lynmouth disaster of 1952 in which 34 people died and 38 houses and buildings were completely destroyed. In the summer of 2004, a severe flash flood devastated the town of Boscastle in Cornwall. However, the worst floods in the United Kingdom in modern times occurred in the North Sea flood of 1953. A powerful storm from the Atlantic moved around Scotland and down the east coast of England. As it moved south it produced a storm surge which was magnified as the North Sea became narrower further south. By the time the storm affected south-east England and the Netherlands, the surge had reached the height of 3.6 metres (12 ft). Over 300 people were killed by the floods in eastern England.

Thunderstorms are most common in southern and eastern England, and least common in the north and west.^[27] As a result of this, inland areas in the south and east tend to have their wettest months in the summer while western, northern and eastern coasts are most likely to have their driest month in the spring and their wettest in late autumn. In London, thunderstorms occur on average 14–19 days a year, while in most of Northern Ireland and the west of Scotland thunderstorms occur on around 3 days a year.^[27]

Strong winds occur mainly in the autumn and winter months associated with low pressure systems. The "Great" storm of 1987 (23 fatalities) and the Burns' Day storm of 1990 (97 fatalities) are particularly severe examples. Relative to its land area, the United Kingdom has more reported tornados than any other country (around 33 per year), excluding the Netherlands, although most are minor.

The most rain to fall on a single day was 279 mm at Martinstown (Dorset) on 18 July 1955.^[14] Heavy rain also fell between 20 and 25 June in 2007; some areas experienced a months rainfall in one day. Four people died in the flooding and over £1.5 billion of damage to businesses and properties was caused.

[edit] Climate history

The climate of the United Kingdom has not always been the way it is today. During some periods it was much warmer and in others it was much colder. The last glacial period was a period of extreme cold weather that lasted for tens of thousands of years and ended about 10,000 years ago. During this period the temperature was so low that much of the surrounding ocean froze and a great ice sheet extended over all of the United Kingdom except the south of England.

The temperature records in England are continuous back to the mid 17th century. The Central England temperature (CET) record is the oldest in the world, and is a compound source of cross-correlated records from several locations in central England.

[edit] See also

• Met Office (UK Meteorological Office)
• United Kingdom Climate Change Programme
• Climate change
• European windstorm
• List of natural disasters in the United Kingdom
• Geography of the United Kingdom
• Climate of Scotland

[edit] References

[edit] External links

• Met Office
• BBC weather centre country guide for the UK