Japan heatwave disaster: Tokyo records 453 heat-related hospitalizations in single day, highest since 2010

Tokyo, July 23, 2026 (AFP) — More than 450 people received hospital treatment for heat-related issues in a single day in Tokyo — the highest number since records began 16 years ago, emergency services said on Thursday.

The figure was released as Japan sweltered in a heatwave that has killed at least 14 people over the past week.

Key Figures

• 453 people hospitalised for heat-related issues on Wednesday (July 22) — the most since records began in 2010, according to the Tokyo Fire Department
• Emergency callouts reached the highest level since at least 1963
• At least 14 deaths reported across the country over the previous week
• 11,000 people sought emergency medical care nationwide

Tokyo Prefecture

In Tokyo prefecture — home to around 14 million people — officials reported:

• One death in the current heatwave
• Four people in critical condition
• 18 people in a serious state

"We are urging people to stay hydrated and use air conditioners," a fire brigade spokesman told AFP.

The number of patients appeared to rise as temperatures climbed, with notable increases on Tuesday and Wednesday, the spokesman said.

'Disaster' Declared

The Fire and Disaster Management Agency has dubbed the heatwave a "disaster".

"It is no exaggeration to call this extreme heat a 'disaster' with many people being rushed to hospitals or even dying as a result of heatstroke," the agency said.

"Temperatures have been rising since mid-July, and severe heat is expected to continue nationwide," it added.

Regional Impact

In the central region of Aichi, which includes Nagoya and is experiencing some of the most intense heat, 116 people were taken to hospital on Wednesday.

Heatstroke alerts have been issued for almost the entire country of around 125 million people.

Record Temperatures

On Thursday, at least six locations recorded temperatures of 40°C or hotter by early afternoon, while the mercury rose to 39.9°C in three other locations.

| Location | Temperature | |----------|-------------| | Hamamatsu (Shizuoka region) | 41.1°C | | Toyota city (Aichi region) | 40.8°C | | Kuwana (Mie region) | 40.7°C |

Japan's highest recorded temperature was registered on August 5, 2025, at 41.8°C in Isesaki, north of Tokyo.

New Terminology

Japan introduced a new term this year to describe heat above 40°C: "kokushobi", which translates to "cruelly hot day".

The term was designed to draw greater public attention to heat-related warnings, although it does not trigger any official measures nationwide.

On the Ground

Nick Estes, 35, an American tourist visiting the Asakusa area of Tokyo with his family, described the weather as "extremely hot".

"We've been planning our trips around trying to make sure we can spend time in the metro to cool off, finding little shops to pop into to maybe buy a little souvenir that has air conditioning, doing everything we can to stay cool," Estes told AFP.

"But especially with younger kids, it's been absolutely brutal... I was here last summer, actually, and somehow it actually feels even hotter this year than it did a year ago."