Western Europe got its first hint of an unusual summer in May 2026, when a heat dome producedexceptional temperaturesthat shattered records in several countries.
Remarkable as it was, that earlyheat waveturned out to be only the opening salvo.
By mid-August, Europeans were sweating through theirfifth heat waveof the season, with the latest onslaught pushing temperatures well above 40 degrees Celsius across a broad area.
During these bouts of extreme weather, high temperatures were often unrelenting, persisting for several days and sometimes weeks on end, and remaining overnight.
For a region accustomed to relatively mild summers, the heat upended everyday life.
Hospitalizations and heat-related deathsspiked.
Highways and train tracksbuckled, forcing road closures andservice disruptions.
Large and destructive wildfiresragedin areas where they were once rarely seen.
The heat also worsened thesevere droughtthat has gripped the region for months, contributing torecord-lowriver water levels and disrupting water and power supplies, transportation routes, and agriculture.
The animation above shows the daily maximum surface air temperature across Western Europe from May 1 to August 19, 2026.
It was produced by combining satellite observations with temperatures predicted by a version of NASA’sGEOS global model, which uses mathematical equations to represent physical processes in the atmosphere.
The darkest red areas indicate where temperatures met or exceeded 40°C.
The heat broke records at a furious pace, often by wide margins.
According to theUK Met Office, temperatures soared as high as 35.1°C in London on May 26, smashing the previous May record by 2.3°C.
In June, Bordeaux, France, broke its maximum-temperature record on three consecutive days, hitting 42.5°C on June 24,Météo-Francereported.
Slovakia, meanwhile, set new national records for bothdaytimeandnighttime highsin August.
Combined June and July temperatures in Western Europe were the highest on record, accordingto Europe’s Copernicus climate monitoring service.
In Europe, extreme temperatures collided with several vulnerabilities, including limited access toair conditioning, high nighttime temperatures, and a lack of green space in some cities.
The circumstances triggered not just discomfort butheat exhaustionandheatstrokein some cases.
Preliminary reports suggest that heat may have been associated with1만 excess deaths, including thousands of people in theUK, France, Germany, and Belgium.
“Air conditioning is an especially critical issue in Europe in the short term,” said Anamika Shreevastava, a researcher at New York University whostudied urban heat islandsas a postdoc at NASA’s Jet Propulsion Laboratory.
One of her goals was to producethermal mapsbased on NASA data from missions likeECOSTRESSthat city planners could use to make cities more resilient to heat waves.
International Energy Agency datashow that 23 percent of homes in Europe have air conditioning, compared to 90 percent of homes in the United States.
That difference contributes to the much higher death rates that researchershave documentedin European cities during heat waves than in comparable American cities. “Longer term, cities can also plant trees, expand parks, use reflective roof paint, and transition to building materials less likely to retain heat,” Shreevastava said.
An analysis from the World Health Organizationindicates that heat stress is the world’s leading cause of weather-related deaths, noting it exacerbates underlying illnesses, including cardiovascular disease, diabetes, mental health conditions, and asthma.
Researchers have calculated that roughly 489,000 heat-related deaths occur each year, with 45 percent of the deaths in Asia and 36 percent in Europe.
“For older adults with physical health problems, temperatures as low as 26.7°C can pose significant danger,” said Deborah Carr, a Boston University sociologist who specializes in the study of aging. “Nighttime heat is especially harmful for older adults whose homes lack air conditioning.”
Carr is part of a research team that used demographic data, along withtemperature and climate dataarchived by NASA,to identifywhich parts of the world are at the greatest risk of current and future heat exposure.
Southern Europe was among the areas facing growing heat exposure and an aging population, the researchers found.
Other research, published inLancet Planetary Healthin August 2026, underscores the importance of demographics in assessing the risks posed by heat.
This study, led by Stanford researcher Qinqin Kong, mapped where increasing heat is likely to lead to intolerable conditions in the coming decades for young, middle-aged, and older adults, concluding that safe thresholds will be breached often and widely, with risks falling disproportionately on older people.
“The human body can tolerate only a limited range of ambient heat,” said Kong, a recipient of aNASA Earth and Space Science and Technology award. “Understanding where, when, and to what extent these limits are exceeded is critical.”
With intolerable levels of heat expected to affect more people across larger regions and for longer periods than previously thought, Kong and his colleagues hope that their findings will inform targeted heat action plans, emergency preparedness, and health system planning.
NASA Earth Observatory image by Lauren Dauphin, usingGEOS-FPdata from the Global Modeling and Assimilation Officeat NASA GSFC. Story by Adam Voiland.
APUK and France prepare for another heat wave as western Europe sets new temperature record. Accessed August 20, 2026.
Copernicus Climate Change ServiceExceptionally hot and dry conditions fuel wildfires in Europe as ocean surface temperatures reach record highs for July. Accessed August 20, 2026.
Copernicus Climate Change ServiceRecord heatwave brings hottest June for western Europe during second-warmest June globally. Accessed August 20, 2026.
Falchetta, G.,et al.Global projections of heat exposure of older adults. Nature Communications, 15, 3678.
Kong, Q.,et al.Exceeding human heat tolerance in a warming, ageing world: a global projection modelling study.The Lancet Planetary Health, In press.
Met OfficeMay 2026 temperature records verified. Accessed August 20, 2026.
NASAGlobal Temperature – Earth Indicator. Accessed August 20, 2026.
NASA EarthdataTraining: Satellite Remote Sensing for Measuring Urban Heat Islands and Constructing Heat Vulnerability Indices. Accessed August 20, 2026.
NASA Earthdata, Heat. Accessed August 20, 2026.
The New YorkTimesEurope Is Once Again in the Grip of a Heat Wave. Accessed August 20, 2026.
ReutersTracking Western Europe’s heatwave. Accessed August 20, 2026.
World Meteorological OrganizationRecord-breaking heat and extreme weather continue. Accessed August 20, 2026.
World Resources InstituteEurope’s Soaring Heat and the Great Air Conditioning Dilemma.
Accessed August 20, 2026.
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