Skip to main contentSkip to navigationSkip to navigation

The hottest summer in human history – a visual timeline

This article is more than 1 year old

From June to August 2023, a series of extreme weather events exacerbated by climate breakdown caused death and destruction across the globe

As the world sweltered through the hottest three month spell in human history this summer, extreme weather disasters took more than 18,000 lives, drove at least 150,000 people from their homes, affected hundreds of millions of others and caused billions of dollars of damage.

That is a conservative tally from the most widely covered disasters between early June and early September, which have been compiled in the timeline below as a reminder of how tough this period has been and what might lie ahead.

June

Haiti

2 June

Misery added to poverty

Flooding in the Portail Leogane, in Port-au-Prince, Haiti. Photograph: Anadolu Agency/Getty Images

Unusually intense rains flood towns and villages, killing 42 and destroying more than 10,000 homes.

Canada

7 June

Fires the size of Greece

Firefighters flying over a controlled burn to fight wildfires in Canada’s Quebec Province. Photograph: Genevieve Poirier/Societe De Protection Des Forets/AFP/Getty Images

Smoke from devastating wildfires in Quebec casts a pall over New York and prompts air quality warnings for tens of millions of people. Over the course of the summer, fires across Canada would go on to burn 17.9m hectares of land, double the previous record. At least six people are killed and thousands evacuated. “The word ‘unprecedented’ doesn’t do justice to the severity of the wildfires in Canada this year,” said Yan Boulanger of Natural Resources Canada. “From a scientific perspective, the doubling of the previous burned area record is shocking.”

The area burned by wildfires in Canada so far this year is more than seven times the yearly average

20m cumulative hectares burned

7 Jun 2023

4.1m ha

close to the size

of Denmark

27 Sep 2023

17.9m ha

close to the

size of Syria

15

10

2003-22

5

2003-22

average

2.4m ha

0

May

Jun

Jul

Aug

Sep

The area burned by wildfires in Canada so far this year is more than seven times the 2003-22 average

20m cumulative hectares burned

27 Sep 2023

17.9m ha

close to the

size of Syria

15

7 Jun 2023

4.1m ha

close to the size

of Denmark

10

2003-22

5

2003-22

average

2.4m ha

0

May

June

July

August

September

Iran

9 June

Killer gales and severe droughts

Severe wind and rain kill seven people and injured 59 in the northwest regions. Authorities later report 97% of the country is experiencing water shortages amid a persistent drought.

Balkans

20-23 June

Hailstones the size of cannonballs and flash floods

A supercell brings hailstones,up to 14cm in diameter, to Slovenia and Croatia, destroying crops and tearing the roofs off houses. At least three people die in flash floods in Kosovo and Romania. “A catastrophe of this magnitude has never been recorded here before,” says the council head of the worst affected Romanian region, Arad County. Serbia declared an emergency in Belgrade and 50 other municipalities. Thousands of homes are damaged.

Antarctic

28 June

Texas-sized decline in sea ice

Sea ice in the southern hemisphere drops 1.2m sq km (roughly the size of Texas) below the previous record low for early winter. Monthly records follow for July and August.

Antarctic sea ice extent, 28 June 2023

Sea ice extent

28 June 2023

June av 1981-2010

June av each year 2000-22

Ice shelves

Southern

Ocean

Weddell

Sea

Antarctica

Ronne

South Pole

90º

W

90º

E

Ross

Antarctic

Circle

Ross

Sea

Southern

Ocean

180º

Antarctic sea ice extent, 28 June 2023

 

Antarctic sea ice extent, 28 June 2023

Sea ice extent

0º

28 June 2023

June av 1981-2010

June av each year 2000-22

Southern

Ocean

Ice shelves

Weddell

Sea

South

America

Antarctica

Ronne

South Pole

90ºW

90ºE

Ross

Ross

Sea

Antarctic

Circle

Southern

Ocean

180º

The annual maximum extent of Antarctic sea ice in 2023 was 1m sq km below the previous record low

Area of ocean with at least 15% sea ice, million sq km

20

All years 1979 to present

1991-2000 average

15

2022

27 Sep 2023

16.6m sq km

10

28 Jun 2023

11.8m sq km

5

0

1 Jan

1 Apr

1 Jul

1 Oct

31 Dec

20

All years 1979 to present

15

1991-2000 average

27 Sep 2023

16.6m sq km

2022

10

28 Jun 2023

11.8m sq km

5

0

1 Jan

1 Apr

1 Jul

1 Oct

31 Dec

South Africa

29 June

Tornado in the southern winter

Seven people die in heavy rain and wind, followed by a tornado in KwaZulu-Natal. Officials in Durban said: “We are experiencing first hand the true effects of climate change during the winter season.”

July

India and Pakistan

5-16 July

The longest-lasting tropical cyclone in the Arabian Sea

People wade through flooded streets after Cyclone Biparjoy made landfall in Mandvi, in the western Indian state of Gujarat. Photograph: Divyakant Solanki/EPA

Cyclone Biparjoy (which means “calamity”) wreaks havoc for 10 days, killing 12 people in India, injuring 12 and forcing the evacuation of 81,000 people in Pakistan. This came amid a devastating monsoon season. New Delhi endured its wettest July day (9 July) in 40 years with 153mm of rain. A landslide in Raigad kills at least 16 with more than 100 feared missing under debris.

China

7 July

Air raid shelters converted into heat refuges

Beijing suspends outdoor work after a tour guide in the Summer Palace collapses and dies on the ninth straight day of temperatures over 35C. Hangzhou and Shijiazhuang open air raid shelters as refuges from the heat. Energy companies say they are burning record amounts of coal to meet the demand for air conditioning.

Japan

10 July

‘Heaviest rain ever’

Six people die in Kyushu during floods and landslides. Meteorological officials describe the deluge as the “heaviest rain ever”.

Italy

12 July

Road worker collapses in the street and dies

People use umbrellas during a heatwave in Milan. Photograph: Mourad Balti Touati/EPA

A 44-year-old road marking painter collapses on the street and dies from heat stress in Lodi, south-east of Milan, as temperatures soar above 40C in Europe’s Cerberus heatwave.

Pakistan

9 July

Grief at monsoon death toll

Monsoon rains lash Lahore and other regions, taking the toll since June to 76 deaths and 133 injuries.

Israel

15 July

Prime minister taken to hospital with dehydration

The Israeli prime minister, Benjamin Netanyahu, is rushed to hospital with suspected dehydration following a day spent in the sun without a hat or water.

China

16 July

All-time heat record shattered

An all-time China temperature record of 52.2C is set in Sanbao, exceeding the previous high by almost two degrees.

Temperature estimates on 16 July, 1900 GMT

-10C

0

10

20

30

40

50

Sanbao, Xinjiang 52.2C China heat record

Pacific

Ocean

Tibetan

Plateau

Indian

Ocean

-10C

0

10

20

30

40

50

Arctic Ocean

Sanbao, Xinjiang 52.2C China heat record

Pacific Ocean

Tibetan

Plateau

Indian Ocean

US

17 July

Death Valley sets world midnight temperature record

Gabriel and Pedro Ambrus de Moraes stand next to a digital display of an unofficial heat reading at Furnace Creek Visitor Center in Death Valley, California. Photograph: Ronda Churchill/AFP/Getty Images

Death Valley records the highest midnight temperature in world history of 48.9C as heat tourists flock to the area.

Mexico

16 July

Surge in heat deaths

The government reports 167 deaths from extreme heat since March, dozens more than the previous year. This comes amid a record-long and wide heatwave that sees temperatures rise to 42C in the Valles Centrales and other areas.

US

16 July

Broken air conditioner proves fatal in record heatwave

A Texan man dies after suffering heat stroke when the air conditioner breaks down in his Harris County home amid extreme temperatures in the southern US. The protracted heatwave stretching from Florida to California breaks 2,300 temperature records, takes dozens of lives and affects close to 100 million people.

Algeria

16 July

Fainting in the road

A 55-year-old man in Relizane dies amid a record heatwave, with temperatures over 50C paralysing outside activity after 10am. About 50 people are taken to hospital after fainting on the street, according to local media.

USA

17 July

Fatal flash floods

A flooded road, in Highland Falls, Orange County, New York. Photograph: Marc Zahakos/Reuters

After days of heavy rain, flash floods sweep across swathes of the US’s north-east, killing at least seven people in Pennsylvania and one in New York, flooding roads, cutting electricity supplies and forcing the cancellation of nearly 1,500 flights.

Spain

17 July

Crisis declared in the olive oil industry

A heatwave and record temperatures in parts of the country (Catalonia records its hottest day with temperatures of 45.3C) scorch crops, leading annual production forecasts to be more than a third below average for the second consecutive year. Extreme weather also threatens rice production in Asia and soy production in the US and South America.

Italy

18 July

Hospitals adopt Covid-style protocols

Medical institutions enter emergency mode to cope with a rise in emergency cases related to heat-stress as temperatures across the country soared to historic highs. Rome bakes in 41.8C, smashing the city’s previous record set last year by more than a degree. In Sardinia, the mercury rose to 45C.

Greece

23 July

Biggest wildfire evacuation in history

Tourists are evacuated from hotels during a wildfire on the Greek island of Rhodes. Photograph: Eurokinissi/AFP/Getty Images

More than 20,000 people are relocated from Rhodes as swathes of the island are engulfed by fire. Greece suffers the longest and most intense heatwave in the country’s history. A national record of 46.4C is set at Gytheio, and Athens is so hot that authorities close the Acropolis at midday.

Italy

24 July

Hailstones damage jetliner wings

A Delta Air Lines flight is forced to make an emergency landing in Rome after its wings are damaged by giant hailstones during a supercell storm in northern Italy. In Lombardy, two people are killed by falling trees.

South Korea

25 June to 26 July

Dozens killed in torrential rains

Forty-seven people are killed in the country’s third most intense monsoon season on record.

China

26-30 July

Beijing’s most intense downpour in history

Floods in the capital kill 44 people. Dozens more die across northern China as some areas received a year’s worth of rain in one week. The economic damage is estimated at more than $2bn. Two weeks after this, a mudslide in Xi’an buries 21 people and forces the evacuation of 17,000 after the consecutive typhoons Khanun and Doksuri.

Russia

July 30

Storm causes campsite carnage

Eight campers are killed and 27 are injured in a fierce storm in Mari El on the bank of the Volga River that brings trees down onto the tents.

July 2023 was the world's hottest month on record

Monthly average global surface temperature anomalies relative to a 1991-2020 baseline

Cooler than avearge

Warmer than avearge

30 hottest months on record

+0.8C

July and August 2023

1st and 2nd hottest

months on record,

June was 8th hottest

+0.4

July 1998

22nd hottest

0

-0.4

-0.8

1980

1990

2000

2010

2020

Monthly average global surface temperature anomalies relative to a 1991-2020 baseline

Cooler than avearge

Warmer than avearge

30 hottest months on record

+0.8C

July 1998

22nd hottest month

on record

+0.4

0

July and August 2023

1st and 2nd hottest

months on record,

June was 8th hottest

-0.4

-0.8

1980

1985

1990

1995

2000

2005

2010

2015

2020

August

UK

4 August

Europe Heatwave costs world 0.6% of GDP

A study by the Allianz insurance company estimates the heatwaves of the previous three months cost the world 0.6% of GDP in lost working hours, even without calculating the greater effects on health, infrastructure and agricultural production. Separately, other insurance companies appear to be reducing their exposure to climate risks by raising premiums and denying cover in areas at high risk of wildfires and storms.

Chile

5 August

Off-the-charts winter heat record in Andean mountains

Freakish winter heat above 37C in the Andean mountains of South America prompts meteorologist to declare: “This event is rewriting all climatic books.”

Slovenia and Georgia

6 August

Deaths after record rain

A month’s worth of rain in just 24 hours soaks Slovenia, killing three and causing an estimated €500m of damage. Nineteen die in a mudslide in the Shovi region of Georgia.

Hawaii

8 August

Deadliest wildfire in US history

An aerial view of burned cars and homes in a neighbourhood that was destroyed by a wildfire in Lahaina, Hawaii. Photograph: Justin Sullivan/Getty Images

An uncontrolled blaze kills at least 97 in Lahaina on Maui island. A drier than usual summer had created tinderbox conditions in an area where fire-resistant native vegetation had long ago been replaced by sugarcane plantations and invasive grasses.

Nepal

8 August

High mountains no refuge from deadly rains

The government announces that landslides and floods during this year’s monsoon have killed 38 people, destroyed countless homes and blocked a major highway.

Greece

22 August

18 migrants killed in EU’s biggest fire

The corpses, including those of two children, found in Dadia national forest are among 21 victims of the biggest wildfire in the EU since records began. Even the local hospital at the regional capital of Alexandroupoli has to be evacuated. Dozens of other fires erupted throughout the summer. A month earlier, 20,000 people, including holidaymakers, were rescued from fires on the island of Rhodes in what was described as the biggest evacuation in modern Greek history.

US

23 August

Morgues run out of space for bodies during record heatwave

Morgues in Maricopa County, Arizona order extra coolers after a record 44 heat related deaths in one week. The previous month, Phoenix endured daily highs over 43.3C (110F) for 31 days in a row (smashing the record of 17 days from 1974).

US

22 August

Hilary smashes state rainfall records

Nevada’s daily rainfall record is doubled during Tropical Storm Hilary, which also set records in Idaho, Montana and Oregon. It had previously swept through Mexico, killing one man, and deluged California.

Tajikistan

28-30 August

Central Asia’s deadly downpour

Three days of torrential rain near the capital caused floods, landslides and mudflows that kill at least 21 people in the central region near Dushanbe.

US

30 August

Heatstroke blamed for record number of migrant deaths

The number of migrant deaths in El Paso hits a record annual high of 136, largely due to extreme heat, according to a US Border Patrol report. This is almost double the figure for the entirety of last year. “Migrants have told us they are being held without sufficient food or water on the Mexican side, or they were waiting for hours in the desert for the opportunity to cross,” said one official.

…And the catastrophe goes on inSeptember

Brazil

5 September

‘Worst ever’ climate catastrophe in southern state

A house hit by an extratropical cyclone in Roca Sales, Rio Grande do Sul state, Brazil. Photograph: Diego Vara/Reuters

The governor of Rio Grande do Sul says his state has suffered its worst ever death toll due to a climate event after an extratropical cyclone kills 31 and leaves over 1,600 homeless.

Hong Kong

8 September

Heaviest rain since records began

The most intense downpour in 140 years kills two and injures more than 100 as Typhoon Haikui sweeps across southern China.

Libya

9-11 September

World’s deadliest weather event of the year.

More than 11,300 people are killed in flooding in the coastal city of Derna after record rainfall leads to the collapse of dams. In a single day, Storm Daniel unleashed 200 times as much rain as usually falls on the city in the entire month of September. Human-induced climate change made this up to 50 times more likely.



Heatwaves, fires, floods and storms occur every year, but their intensity is being steadily amplified by human-caused climate disruption, and in 2023, given an extra boost by an El Niño. Scientists have examined a selection of these events and found human emissions massively loaded the dice in favour of disaster.

The final death toll from these months is likely to be far higher than the casualty figures reported at the time because excess heat deaths take many months to calculate.

It is also a taste of more to come. This summer’s heatwave – or worse – is forecast to occur two out of every five years if global heating reaches 2C above pre-industrial levels, and the world is currently on course to go much higher in the coming decades.

This article was amended on 29 September 2023. An earlier version said An uncontrolled blaze in Lahaina on Maui island killed 115 people; this was the original figure at the time of the fire but that was later revised to 97.

Most viewed

Most viewed