The United Kingdom straddles the higher mid-latitudes between 49° and 61°N on the western seaboard of Europe. Since the UK is always in or close to the path of the polar front jet stream, frequent changes in pressure and unsettled weather are typical. Many types of weather can be experienced in a single day. The basic climate of the UK annually is wet and cool in winter, spring, and autumn with frequent cloudy skies, and drier and cool to mild in summer.
A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather. A time period of five consecutive days is often used to define a heat wave but the exact definition of a heat waves can vary for different countries. A heat wave is usually measured relative to the usual climate in the area and to normal temperatures for the season. Temperatures that humans from a hotter climate consider normal, can be regarded as a heat wave in a cooler area. This would be the case if the warm temperatures are outside the normal climate pattern for that area. High humidity often occurs during heat waves as well. This is especially the case in oceanic climate countries. Heat waves have become more frequent, and more intense over land, across almost every area on Earth since the 1950s, the increase in frequency and duration being caused by climate change.
The 2003 European heat wave saw the hottest summer recorded in Europe since at least 1540. France was hit especially hard. The heat wave led to health crises in several countries and combined with drought to create a crop shortfall in parts of Southern Europe. The death toll has been estimated at more than 70,000.
A period of unusually hot summer weather occurred in the British Isles during the summer of 1976. At the same time, there was a severe drought on the islands of Great Britain and Ireland. It was one of the driest, sunniest and warmest summers (June/July/August) in the 20th century, although the summer of 1995 is now regarded as the driest. Only a few places registered more than half their average summer rainfall. In the Central England temperature record, it was the warmest summer in the series until being surpassed in the 21st century. It was the warmest summer in the Aberdeen area since at least 1864, and the driest summer since 1868 in Glasgow.
The 2006 European heat wave was a period of exceptionally hot weather that arrived at the end of June 2006 in certain European countries. The United Kingdom, France, Belgium, the Netherlands, Luxembourg, Italy, Poland, the Czech Republic, Hungary, Germany and western parts of Russia were most affected.
The British Isles are an archipelago off the northwest coast of Europe, consisting of the islands of Great Britain and Ireland along with smaller surrounding ones. Its position allows dry continental air from Eurasia to meet wetter air from the Atlantic Ocean, which causes the weather to be highly variable, often changing many times during the day. It is defined as a temperate oceanic climate, or Cfb on the Köppen climate classification system. It is significantly warmer than other regions on the same latitude generally thought to be due to the warmth provided by the Gulf Stream; however there is an alternative hypothesis that it is caused by the Rocky Mountains and the heat storing capabilities of the North Atlantic Ocean. Temperatures do not often switch between great extremes, with warm summers and mild winters.
MeteoGroup was a private weather forecasting organisation based in Europe, with offices in Belgium, Canada, France, Germany, Ireland, Italy, the Netherlands, the Philippines, Poland, Singapore, Spain, Sweden, Switzerland, Turkey, the United Kingdom, and the United States. MeteoGroup provided weather information to markets that included transport, marine, agriculture, energy and the media. MeteoGroup had a portfolio of weather apps: WeatherPro, MeteoEarth and Magical Weather. In 2013, MeteoGroup was acquired by General Atlantic. In 2018, MeteoGroup was acquired by TBG AG.
Droughts are a relatively common feature of the weather in the United Kingdom, with one around every 5–10 years on average. These droughts are usually during the summer, when a blocking high causes hot, dry weather for an extended period. However this means that droughts can vary in their characteristics. All types of drought cause issues across all sectors, with impacts extending to the ecosystem, agriculture and the economy of the whole country in severe cases of drought. The south east of the country usually suffers most, as it has the highest population and the lowest average precipitation per year, which is even lower in a drought. Even in these areas in severe droughts, the definition, impacts, effects and management are all minimal in comparison to drought prone areas such as Australia and parts of the United States. In recent years however, the summers of 2007, 2008, 2009, August 2010 and 2012 were wetter than normal, 2007 being wettest on record. Droughts have continued to occur in recent times, with spring 2011, July 2013, summer 2018, spring 2020, spring and summer 2022 and May and June 2023 all featuring excessively dry periods for part or all of the UK, and will likely become more severe due to climate change over the 21st century.
During the 1990 heat wave in the United Kingdom a weather station recorded a temperature of 37.1 °C (98.8 °F) for Cheltenham, Gloucestershire, the highest temperature ever known in Britain, one full Fahrenheit degree above the previous record, set in 1911.
The United Kingdom heatwave of 1911 was a particularly severe heatwave and associated drought. Records were set around the country for temperature in England, including the highest accepted temperature, at the time, of 36.7 °C (98.1 °F), only broken 79 years later in the 1990 heatwave, which reached 37.1 °C (98.8 °F). A temperature of 100 °F (38 °C) was recorded at Greenwich in a Glaisher stand and was regarded as the record but further data from a Stevenson screen in the same location showed the temperature to be 96.6 °F (35.9 °C). The highest ever accepted temperature is currently 40.3 °C (104.5 °F) recorded on 19th July 2022 on a Royal Air Force station in Coningsby, Lincolnshire. Weather in Northern Europe was also affected around about this time.
The 2013 extreme weather events included several all-time temperature records in Northern and Southern Hemisphere. The February extent of snow cover in Eurasia and North America was above average, while the extent of Arctic ice in the same month was 4.5% below the 1981–2010 average. The Northern Hemisphere weather extremes have been linked to the melting of Arctic sea ice, which alters atmospheric circulation in a way that leads to more snow and ice.
The 2013 heatwave in the United Kingdom and Ireland was a period of unusually hot weather primarily in July 2013, with isolated warm days in June and August. A prolonged high pressure system over Great Britain and Ireland caused higher than average temperatures for 19 consecutive days in July, reaching 33.5 °C (92.3 °F) at Heathrow and Northolt.
The 1995 British Isles heatwave occurred between late July and late August. It was part of one of the warmest summers recorded in the UK, and one of the warmest Augusts ever recorded in many locations around the UK, as well as being one of the driest summers ever recorded in the UK; many weather stations recorded the summer of 1995 as drier than, or comparable with, the summer of 1976. Ireland was also widely affected by the heatwave with temperatures reaching over 30 °C (86 °F) in some locations, as well as exceptionally low rainfall throughout the summer.
The 2018 Britain and Ireland heatwave was a period of unusually hot weather that took place in June, July and August. It caused widespread drought, hosepipe bans, crop failures, and a number of wildfires. These wildfires worst affected northern moorland areas around the Greater Manchester region, the largest was at Saddleworth Moor and another was at Winter Hill, together these burned over 14 square miles (36 km2) of land over a period of nearly a month.
A tropical night is a term used in many European countries to describe days when the temperature does not fall below 20 °C (68.0 °F) during the nighttime. This definition is in use in countries including the Austria, Croatia, Denmark, Finland, Germany, Greece, Hungary, Italy, the Republic of Ireland, Latvia, Lithuania, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Spain, Sweden and the United Kingdom. In the United States, by contrast, the term sultry nights is used when the temperature does not fall below 27 °C (80.6 °F) in the Gulf and Atlantic states.
In late June and late July 2019 there were two temporally distinct European heat waves, which set all-time high temperature records in Belgium, France, Germany, Luxembourg, the Netherlands, and the United Kingdom.
The 2021 Britain and Ireland heat wave was a period of unusually hot weather in July 2021 that led to record-breaking temperatures in the UK and Ireland.
The 2022 United Kingdom heatwaves were part of several heatwaves across Europe and North Africa. The United Kingdom experienced three heatwaves; the first was for three days in June, the second for three days in July, and the third for six days in August. Climatologists say the extreme heat was due to climate change. 2022 was the UK's warmest year since records began in 1884, with an average annual temperature above 10 °C (50 °F) for the first time. The 2022 heatwaves contributed to the death of nearly 3000 people, most of whom were 65 years or older.
From June to August 2022, persistent heatwaves affected parts of Europe, causing evacuations and killing tens of thousands. These heat waves were the deadliest meteorological events in 2022. The highest temperature recorded was 47.0 °C (116.6 °F) in Pinhão, Portugal, on 14 July.
