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A heat wave, or heatwave,is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.
The term is applied both to hot weather variations and to extraordinary spells of hot which may occur only once a century. Severe heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning. A heat wave is considered extreme weather that can be a natural disaster, and a danger because heat and sunlight may overheat the human body. Heat waves can usually be detected using forecasting instruments so that a warning call can be issued.
A definition based on Frich et al.'s Heat Wave Duration Index is that a heat wave occurs when the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C (9 °F ), the normal period being 1961–1990.
A formal, peer-reviewed definition from the Glossary of Meteorology is:
The World Meteorological Organization, defines a heat wave as 5 or more consecutive days of prolonged heat in which the daily maximum temperature is higher than the average maximum temperature by 5 °C (9 °F) or more. However, some nations have come up with their own criteria to define a heat wave.
In the Netherlands, a heat wave is defined as a period of at least 5 consecutive days in which the maximum temperature in De Bilt exceeds 25 °C (77 °F), provided that on at least 3 days in this period the maximum temperature in De Bilt exceeds 30 °C (86 °F). This definition of a heat wave is also used in Belgium and Luxembourg.
In Denmark, a national heat wave (hedebølge) is defined as a period of at least 3 consecutive days of which period the average maximum temperature across more than fifty percent of the country exceeds 28 °C (82.4 °F) – the Danish Meteorological Institute further defines a "warmth wave" (varmebølge) when the same criteria are met for a 25 °C (77.0 °F) temperature, while in Sweden, a heat wave is defined as at least 5 days in a row with a daily high exceeding 25 °C (77.0 °F).
In the United States, definitions also vary by region; however, a heat wave is usually defined as a period of at least two or more days of excessively hot weather. 90 °F (32.2 °C), but not always as this ties in with humidity levels to determine a heat index threshold. The same does not apply to drier climates. A heat storm is a Californian term for an extended heat wave. Heat storms occur when the temperature reaches 100 °F (37.8 °C) for three or more consecutive days over a wide area (tens of thousands of square miles). The National Weather Service issues heat advisories and excessive heat warnings when unusual periods of hot weather are expected.In the Northeast, a heat wave is typically defined as three consecutive days where the temperature reaches or exceeds
In Adelaide, South Australia, a heat wave is defined as five consecutive days at or above 35 °C (95 °F), or three consecutive days at or over 40 °C (104 °F). The Australian Bureau of Meteorology defines a heat wave as "three days or more of maximum and minimum temperatures that are unusual for the location". Until the introduction of this new Pilot Heatwave Forecast there was no national definition that described heatwave or measures of heatwave severity.
In the United Kingdom, the Met Office operates a Heat Health Watch system which places each Local Authority region into one of four levels. Heatwave conditions are defined by the maximum daytime temperature and minimum nighttime temperature rising above the threshold for a particular region. The length of time spent above that threshold determines the particular level. Level 1 is normal summer conditions. Level 2 is reached when there is a 60% or higher risk that the temperature will be above the threshold levels for two days and the intervening night. Level 3 is triggered when the temperature has been above the threshold for the preceding day and night, and there is a 90% or higher chance that it will stay above the threshold in the following day. Level 4 is triggered if conditions are more severe than those of the preceding three levels. Each of the first three levels is associated with a particular state of readiness and response by the social and health services, and Level 4 is associated with more widespread response.
A more general indicator that allows comparing heat waves in different regions of the World, characterized by different climates, has been recently developed.This was used to estimate heat waves occurrence at the global scale from 1901 to 2010, finding a substantial and sharp increase in the amount of affected areas in the last two decades.
Heat waves form when high pressure aloft (from 10,000–25,000 feet (3,000–7,600 metres)) strengthens and remains over a region for several days up to several weeks. This is common in summer (in both Northern and Southern Hemispheres) as the jet stream 'follows the sun'. On the equator side of the jet stream, in the upper layers of the atmosphere, is the high pressure area.
Summertime weather patterns are generally slower to change than in winter. As a result, this upper level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface, warming and drying adiabatically. This warmer sinking air creates a high level inversion that acts as a dome capping the atmosphere, inhibiting convection, thereby trapping high humidity warm air below it. Typically, convection is present along the periphery of the cap where the pressure becomes less. This peripheral convection, however, can add to the high pressure dome by ventilating the upper level outflow of the thunderstorms into it. The end result is a continual build-up of heat at the surface that people experience as a heat wave.
In the Eastern United States a heat wave can occur when a high pressure system originating in the Gulf of Mexico becomes stationary just off the Atlantic Seaboard (typically known as a Bermuda High). Hot humid air masses form over the Gulf of Mexico and the Caribbean Sea while hot dry air masses form over the desert Southwest and northern Mexico. The SW winds on the back side of the High continue to pump hot, humid Gulf air northeastward resulting in a spell of hot and humid weather for much of the Eastern States.
In the Western Cape Province of South Africa, a heat wave can occur when a low pressure offshore and high pressure inland air combine to form a Bergwind. The air warms as it descends from the Karoo interior, and the temperature will rise about 10 °C from the interior to the coast. Humidities are usually very low, and the temperatures can be over 40 °C in summer. The highest official temperatures recorded in South Africa (51.5 °C) was recorded one summer during a bergwind occurring along the Eastern Cape coastline.
Global warming boosts the probability of extreme weather events, like heat waves, far more than it boosts more moderate events.
|80 °F (27 °C)||82 °F (28 °C)||84 °F (29 °C)||86 °F (30 °C)||88 °F (31 °C)||90 °F (32 °C)||92 °F (33 °C)||94 °F (34 °C)||96 °F (36 °C)||98 °F (37 °C)||100 °F (38 °C)||102 °F (39 °C)||104 °F (40 °C)||106 °F (41 °C)||108 °F (42 °C)||110 °F (43 °C)|
|40%||80 °F (27 °C)||81 °F (27 °C)||83 °F (28 °C)||85 °F (29 °C)||88 °F (31 °C)||91 °F (33 °C)||94 °F (34 °C)||97 °F (36 °C)||101 °F (38 °C)||105 °F (41 °C)||109 °F (43 °C)||114 °F (46 °C)||119 °F (48 °C)||124 °F (51 °C)||130 °F (54 °C)||136 °F (58 °C)|
|45%||80 °F (27 °C)||82 °F (28 °C)||84 °F (29 °C)||87 °F (31 °C)||89 °F (32 °C)||93 °F (34 °C)||96 °F (36 °C)||100 °F (38 °C)||104 °F (40 °C)||109 °F (43 °C)||114 °F (46 °C)||119 °F (48 °C)||124 °F (51 °C)||130 °F (54 °C)||137 °F (58 °C)|
|50%||81 °F (27 °C)||83 °F (28 °C)||85 °F (29 °C)||88 °F (31 °C)||91 °F (33 °C)||95 °F (35 °C)||99 °F (37 °C)||103 °F (39 °C)||108 °F (42 °C)||113 °F (45 °C)||118 °F (48 °C)||124 °F (51 °C)||131 °F (55 °C)||137 °F (58 °C)|
|55%||81 °F (27 °C)||84 °F (29 °C)||86 °F (30 °C)||89 °F (32 °C)||93 °F (34 °C)||97 °F (36 °C)||101 °F (38 °C)||106 °F (41 °C)||112 °F (44 °C)||117 °F (47 °C)||124 °F (51 °C)||130 °F (54 °C)||137 °F (58 °C)|
|60%||82 °F (28 °C)||84 °F (29 °C)||88 °F (31 °C)||91 °F (33 °C)||95 °F (35 °C)||100 °F (38 °C)||105 °F (41 °C)||110 °F (43 °C)||116 °F (47 °C)||123 °F (51 °C)||129 °F (54 °C)||137 °F (58 °C)|
|65%||82 °F (28 °C)||85 °F (29 °C)||89 °F (32 °C)||93 °F (34 °C)||98 °F (37 °C)||103 °F (39 °C)||108 °F (42 °C)||114 °F (46 °C)||121 °F (49 °C)||128 °F (53 °C)||136 °F (58 °C)|
|70%||83 °F (28 °C)||86 °F (30 °C)||90 °F (32 °C)||95 °F (35 °C)||100 °F (38 °C)||105 °F (41 °C)||112 °F (44 °C)||119 °F (48 °C)||126 °F (52 °C)||134 °F (57 °C)|
|75%||84 °F (29 °C)||88 °F (31 °C)||92 °F (33 °C)||97 °F (36 °C)||103 °F (39 °C)||109 °F (43 °C)||116 °F (47 °C)||124 °F (51 °C)||132 °F (56 °C)|
|80%||84 °F (29 °C)||89 °F (32 °C)||94 °F (34 °C)||100 °F (38 °C)||106 °F (41 °C)||113 °F (45 °C)||121 °F (49 °C)||129 °F (54 °C)|
|85%||85 °F (29 °C)||90 °F (32 °C)||96 °F (36 °C)||102 °F (39 °C)||110 °F (43 °C)||117 °F (47 °C)||126 °F (52 °C)||135 °F (57 °C)|
|90%||86 °F (30 °C)||91 °F (33 °C)||98 °F (37 °C)||105 °F (41 °C)||113 °F (45 °C)||122 °F (50 °C)||131 °F (55 °C)|
|95%||86 °F (30 °C)||93 °F (34 °C)||100 °F (38 °C)||108 °F (42 °C)||117 °F (47 °C)||127 °F (53 °C)|
|100%||87 °F (31 °C)||95 °F (35 °C)||103 °F (39 °C)||112 °F (44 °C)||121 °F (49 °C)||132 °F (56 °C)|
The heat index (as shown in the table above) is a measure of how hot it feels when relative humidity is factored with the actual air temperature. Hyperthermia, also known as heat stroke, becomes commonplace during periods of sustained high temperature and humidity. Older adults, very young children, and those who are sick or overweight are at a higher risk for heat-related illness. The chronically ill and elderly are often taking prescription medications (e.g., diuretics, anticholinergics, antipsychotics, and antihypertensives) that interfere with the body's ability to dissipate heat.
Heat edema presents as a transient swelling of the hands, feet, and ankles and is generally secondary to increased aldosterone secretion, which enhances water retention. When combined with peripheral vasodilation and venous stasis, the excess fluid accumulates in the dependent areas of the extremities. The heat edema usually resolves within several days after the patient becomes acclimated to the warmer environment. No treatment is required, although wearing support stockings and elevating the affected legs will help minimize the edema.
Heat rash, also known as prickly heat, is a maculopapular rash accompanied by acute inflammation and blocked sweat ducts. The sweat ducts may become dilated and may eventually rupture, producing small pruritic vesicles on an erythematous base. Heat rash affects areas of the body covered by tight clothing. If this continues for a duration of time it can lead to the development of chronic dermatitis or a secondary bacterial infection. Prevention is the best therapy. It is also advised to wear loose-fitting clothing in the heat. However, once heat rash has developed, the initial treatment involves the application of chlorhexidine lotion to remove any desquamated skin. The associated itching may be treated with topical or systemic antihistamines. If infection occurs a regimen of antibiotics is required.
Heat cramps are painful, often severe, involuntary spasms of the large muscle groups used in strenuous exercise. Heat cramps tend to occur after intense exertion. They usually develop in people performing heavy exercise while sweating profusely and replenishing fluid loss with non-electrolyte containing water. This is believed to lead to hyponatremia that induces cramping in stressed muscles. Rehydration with salt-containing fluids provides rapid relief. Patients with mild cramps can be given oral .2% salt solutions, while those with severe cramps require IV isotonic fluids. The many sport drinks on the market are a good source of electrolytes and are readily accessible.
Heat syncope is related to heat exposure that produces orthostatic hypotension. This hypotension can precipitate a near-syncopal episode. Heat syncope is believed to result from intense sweating, which leads to dehydration, followed by peripheral vasodilation and reduced venous blood return in the face of decreased vasomotor control. Management of heat syncope consists of cooling and rehydration of the patient using oral rehydration therapy (sport drinks) or isotonic IV fluids. People who experience heat syncope should avoid standing in the heat for long periods of time. They should move to a cooler environment and lie down if they recognize the initial symptoms. Wearing support stockings and engaging in deep knee-bending movements can help promote venous blood return.
Heat exhaustion is considered by experts to be the forerunner of heat stroke (hyperthermia). It may even resemble heat stroke, with the difference being that the neurologic function remains intact. Heat exhaustion is marked by excessive dehydration and electrolyte depletion. Symptoms may include diarrhea, headache, nausea and vomiting, dizziness, tachycardia, malaise, and myalgia. Definitive therapy includes removing patients from the heat and replenishing their fluids. Most patients will require fluid replacement with IV isotonic fluids at first. The salt content is adjusted as necessary once the electrolyte levels are known. After discharge from the hospital, patients are instructed to rest, drink plenty of fluids for 2–3 hours, and avoid the heat for several days. If this advice is not followed it may then lead to heat stroke.
One public health measure taken during heat waves is the setting-up of air-conditioned public cooling centers.
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Heat waves are the most lethal type of weather phenomenon in the United States. Between 1992 and 2001, deaths from excessive heat in the United States numbered 2,190, compared with 880 deaths from floods and 150 from hurricanes.The average annual number of fatalities directly attributed to heat in the United States is about 400. The 1995 Chicago heat wave, one of the worst in US history, led to approximately 739 heat-related deaths over a period of 5 days. Eric Klinenberg has noted that in the United States, the loss of human life in hot spells in summer exceeds that caused by all other weather events combined, including lightning, rain, floods, hurricanes, and tornadoes. Despite the dangers, Scott Sheridan, professor of geography at Kent State University, found that less than half of people 65 and older abide by heat-emergency recommendations like drinking lots of water. In his study of heat-wave behavior, focusing particularly on seniors in Philadelphia, Phoenix, Toronto, and Dayton, Ohio, he found that people over 65 "don't consider themselves seniors." One of his older respondents said: "Heat doesn't bother me much, but I worry about my neighbors."
According to the Agency for Health care Research and Quality, about 6,200 Americans are hospitalized each summer due to excessive heat, and those at highest risk are poor, uninsured or elderly. 49 °C (120 °F).More than 70,000 Europeans died as a result of the 2003 European heat wave. Also more than 2,000 people died in Karachi, Pakistan in June 2015 due to a severe heat wave with temperatures as high as
Our concern now is focusing on predicting the future likelihood of heat waves and their severity. In addition, because in most of the world most of those suffering the impacts of a heat wave will be inside a building, and this will modify the temperatures they are exposed to, there is the need to link climate models to building models. This means producing example time series of future weather.Other work has shown that future mortality due to heat waves could be reduced if buildings were better designed to modify the internal climate, or if the occupants were better educated about the issues, so they can take action in time.
The number of heat fatalities is likely highly underreported due to a lack of reports and misreports.Part of the mortality observed during a heat wave, however, can be attributed to a so-called "harvesting effect", a term for a short-term forward mortality displacement. It has been observed that for some heat waves, there is a compensatory decrease in overall mortality during the subsequent weeks after a heat wave. Such compensatory reductions in mortality suggest that heat affects especially those so ill that they "would have died in the short term anyway".
Another explanation for underreporting is the social attenuation in most contexts of heat waves as a health risk. As shown by the deadly French heat wave in 2003, heat wave dangers result from the intricate association of natural and social factors.
In addition to physical stress, excessive heat causes psychological stress, to a degree which affects performance, and is also associated with an increase in violent crime.High temperatures are associated with increased conflict both at the interpersonal level and at the societal level. In every society, crime rates go up when temperatures go up, particularly violent crimes such as assault, murder, and rape. Furthermore, in politically unstable countries, high temperatures are an aggravating factor that lead toward civil wars.
Additionally, high temperatures have a significant effect on income. A study of counties in the United States found that economic productivity of individual days declines by about 1.7% for each degree Celsius above 15 °C (59 °F).
Abnormally hot temperatures can cause electricity demand to increase during the peak summertime hours of 4 to 7 p.m. when air conditioners are straining to overcome the heat. If a hot spell extends to three days or more, however, nighttime temperatures do not cool down, and the thermal mass in homes and buildings retains the heat from previous days. This heat build-up causes air conditioners to turn on earlier and to stay on later in the day. As a result, available electricity supplies are challenged during a higher, wider, peak electricity consumption period.[ citation needed ]
Heat waves often lead to electricity spikes due to increased air conditioning use, which can create power outages, exacerbating the problem. During the 2006 North American heat wave, thousands of homes and businesses went without power, especially in California. In Los Angeles, electrical transformers failed, leaving thousands without power for as long as five days.The 2009 South Eastern Australia Heat Wave caused the city of Melbourne, Australia to experience some major power disruptions which left over half a million people without power as the heat wave blew transformers and overloaded a power grid.
If a heat wave occurs during a drought, which dries out vegetation, it can contribute to bushfires and wildfires. During the disastrous heat wave that struck Europe in 2003, fires raged through Portugal, destroying over 3,010 square kilometres (1,160 sq mi) or 301,000 hectares (740,000 acres) of forest and 440 square kilometres (170 sq mi) or 44,000 hectares (110,000 acres) of agricultural land and causing an estimated €1 billion worth of damage. High end farmlands have irrigation systems to back up crops with. Heat waves cause wildfires.
Heat waves can and do cause roads and highways to buckle and melt,water lines to burst, and power transformers to detonate, causing fires. See the 2006 North American heat wave article about heat waves causing physical damage.
Heat waves can also damage rail roads, such as buckling and kinking rails, which can lead to slower traffic, delays, and even cancellations of service when rails are too dangerous to traverse by trains. Sun kinking is caused when certain types of rail design like short section rails welded together or fish plate rails expand and push on other sections of rail causing them to warp and kink. Sun kinking can be a serious problem in hotter climates like Southern USA, parts of Canada, the Middle East, etc.
In the 2013 heatwave in England, gritters (normally only seen in snow) were sent out to grit melting tarmac roads.
Climate models reveal that future heat waves will have a more intense geographic pattern.Model results show that areas associated with the severe heat waves in Chicago in 1995 and Paris in 2003 will experience more intense, more frequent, and longer-lasting heat waves in the second half of the 21st century. Heat waves today in Europe and North America happen parallel to the conditions of atmospheric circulation. Increased anthropogenic activities causing increased greenhouse gas emissions show that heat waves will be more severe.
Heat waves and droughts as a result, minimize ecosystem carbon uptake.Carbon uptake is also known as carbon sequestration. Extreme heat wave events are predicted to happen with increased global warming, which puts stress on ecosystems. Stress on ecosystems due to future intensified heat waves will reduce biological productivity. This will cause changes in the ecosystem's carbon cycle feedback because there will be less vegetation to hold the carbon from the atmosphere, which will only contribute more to atmospheric warming.
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June 2019 was the hottest month on record worldwide, the effects of this were especially prominent in Europe.The effects of climate change have been projected to make heat waves in places such as Europe up to five times more likely to occur. Among other effects, increased wildfires in places such as Spain can also be attributed to heat waves.
In July 2019, over 50 million people in the United States were present in a jurisdiction with any type of heat advisory - heat is the deadliest type of extreme weather in the United States. Scientists predicted that in the days following the issuance of these warnings, many records for highest low temperatures will be broken. (I.e. - the lowest temperature in a 24-hour period will be higher than any low temperature measured before.)
Extreme weather or extreme climate events includes unexpected, unusual, severe, or unseasonal weather; weather at the extremes of the historical distribution—the range that has been seen in the past. Often, extreme events are based on a location's recorded weather history and defined as lying in the most unusual ten percent.
The 1995 Chicago heat wave was a heat wave which led to 739 heat-related deaths in Chicago over a period of five days. Most of the victims of the heat wave were elderly poor residents of the city, who could not afford air conditioning and did not open windows or sleep outside for fear of crime. The heat wave also heavily impacted the wider Midwestern region, with additional deaths in both St. Louis, Missouri and Milwaukee, Wisconsin.
The 2003 European heat wave led to the hottest summer on record 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. Peer-reviewed analysis places the European death toll at more than 70,000.
The climate of Chicago is classified as hot-summer humid continental, with all four seasons distinctly represented: Winters are cold and see frequent snow and near 0 F windchill temperatures, while summers are warm and humid with temperatures being hotter inland, spring and fall bring bouts of both cool and warm weather and fairly sunny skies. Annual precipitation in Chicago is moderate and relatively evenly distributed, the driest months being January and February and the wettest July and August. Chicago's weather is influenced during all four seasons by the nearby presence of Lake Michigan.
Adelaide has a Mediterranean climate, with cool to mild winters with moderate rainfall and warm to hot, generally dry summers.
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. Several records were broken. In the Netherlands, Belgium, Germany, Ireland and the United Kingdom, July 2006 was the warmest month since official measurements began.
The climate of Sydney is humid subtropical, shifting from mild and cool in winter to warm and hot in the summer, with no extreme seasonal differences as the weather is moderated by proximity to the ocean, although more contrasting temperatures are recorded in the inland western suburbs. Despite the fact that there is no distinct dry or wet season, rainfall peaks in the first half of the year and is at its lowest in the second half. Precipitation varies across the region, with areas adjacent to the coast being the wettest. The city receives around 20 thunderstorms per year.
The climate of Delhi is an overlap between monsoon-influenced humid subtropical and semi-arid, with high variation between summer and winter temperatures and precipitation. Delhi's version of a humid subtropical climate is markedly different from many other humid subtropical cities such as Sao Paulo, New Orleans and Brisbane in that the city features dust storms and wildfire haze due to its semi-arid climate.
Australia's climate is governed mostly by its size and by the hot, sinking air of the subtropical high pressure belt. This moves north-west and north-east with the seasons. The climate is variable, with frequent droughts lasting several seasons, thought to be caused in part by the El Niño-Southern Oscillation. Australia has a wide variety of climates due to its large geographical size. The largest part of Australia is desert or semi-arid. Only the south-east and south-west corners have a temperate climate and moderately fertile soil. The northern part of the country has a tropical climate, varying between grasslands and desert. Australia holds many heat-related records: the continent has the hottest extended region year-round, the areas with the hottest summer climate, and the highest sunshine duration.
The 1906 United Kingdom heat wave occurred across Great Britain in the months of August and September. The heat wave had a comparable intensity to the 1990 heat wave. From 31 August to 3 September, the temperature in the UK exceeded 32 °C (90 °F) consecutively over most of the UK on these four days. In September, CET Central England and Birmingham recorded a highest temperature of 31.5 °C (88.7 °F), and Oxford recorded a highest temperature of 33.1 °C (91.6 °F), the Oxford high surpassed in 1911 with a temperature of 33.4 °C (92.1 °F).
This article is about climate change, industry and society.
The 2010 Northern Hemisphere summer heat waves included severe heat waves that impacted most of the United States, Kazakhstan, Mongolia, China, Hong Kong, North Africa and the European continent as a whole, along with parts of Canada, Russia, Indochina, South Korea and Japan during May, June, July, and August 2010. The first phase of the global heatwaves was caused by a moderate El Niño event, which lasted from June 2009 to May 2010. The first phase lasted only from April 2010 to June 2010, and caused only moderate above average temperatures in the areas affected. But it also set new record high temperatures for most of the area affected, in the Northern Hemisphere. The second phase was caused by a very strong La Niña event, which lasted from June 2010 to June 2011. According to meteorologists, the 2010–11 La Niña event was one of the strongest La Niña events ever observed. That same La Niña event also had devastating effects in the Eastern states of Australia. The second phase lasted from June 2010 to October 2010, caused severe heat waves, and multiple record-breaking temperatures. The heatwaves began on April 2010, when strong anticyclones began to develop, over most of the affected regions, in the Northern Hemisphere. The heatwaves ended in October 2010, when the powerful anticyclones over most of the affected areas dissipated.
The Australian summer of 2012–2013, known as the Angry Summer or Extreme Summer, resulted in 123 weather records being broken over a 90-day period, including the hottest day ever recorded for January on record, the hottest summer average on record, and a record seven days in a row when the whole country averaged above 39 °C (102 °F). Single-day temperature records were broken in dozens of towns and cities, as well as single-day rainfall records, and several rivers flooded to new record highs.
The 2016 Indian heat wave was a major heat wave in April and May of that year. A national record high temperature of 51.0 °C (123.8 °F) was set in the town of Phalodi, in the state of Rajasthan. Over 160 people died with 330 million affected to some degree. There were also water shortages with drought worsening the impact of the heat wave.
The 2018 Britain and Ireland heat wave 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. It is now known as the Love Island/ World Cup Summer.
The 2018 European drought and heat wave was a period of unusually hot weather that led to record-breaking temperatures and wildfires in many parts of Europe during the spring and summer of 2018. It is part of a larger heat wave affecting the northern hemisphere, caused in part by the jet stream being weaker than usual, allowing hot high-pressure air to linger in the same place. According to the European Drought Observatory, most of the areas affected by drought are across northern and central Europe.
In 2018, several heat waves with temperatures far above the long-time average and droughts were recorded in the Northern Hemisphere: The earth's average surface temperature in 2018 was the fourth highest in the 140 years of record keeping. It is assumed that the jet stream is slowing down, trapping cloudless, windless and extremely hot regions of high pressure. The jet stream anomalies could be caused by polar amplification, one of the observed effects of global warming.
From mid-May to mid-June 2019, India and Pakistan had a severe heat wave. It was one of the hottest and longest heat waves since the two countries began recording weather reports. The highest temperatures occurred in Churu, Rajasthan, reaching up to 50.8 °C (123.4 °F), a near record high in India, missing the record of 51.0 °C (123.8 °F) set in 2016 by a fraction of a degree. As of 12 June 2019, 32 days are classified as parts of the heatwave, making it the second longest ever recorded.
The July 2019 European heat wave was a period of exceptionally hot weather, setting all-time high temperature records in Belgium, Germany, Luxembourg, the Netherlands, and the United Kingdom. It followed the June 2019 European heat wave, which killed over 567 people, and exceeded previous records by 3 °C (5.4 °F) in Belgium, by 0.3 °C (0.54 °F) in Luxembourg, by 2.1 °C (3.8 °F) in Germany and the Netherlands and by 0.2 °C (0.36 °F) in the United Kingdom.