Tokyo records highest number of heat-related hospitalizations in a single day since 2010

Tokyo recorded its highest number of heat-related hospitalizations in a single day since 2010 on Wednesday, with one death and four people in critical condition, emergency services announced on Thursday, as a severe heatwave sweeps across Japan.

Firefighters in the Japanese capital reported that 453 people were transported to hospitals on Wednesday across Tokyo Metropolis, setting a record since data recording began in 2010, and that the deployment of emergency services reached levels unseen for at least 63 years.

A spokesperson for the Fire and Disaster Management Agency told Agence France-Presse on Thursday, “We urge the general public to drink sufficient amounts of water and use air conditioning.”

He added, “It appears the number of patients has increased alongside rising temperatures. We saw notable increases yesterday (Wednesday) and the day before.”

Tokyo firefighters also responded to 3,612 calls on Wednesday, a record high since data recording began in 1963, according to a spokesperson for the agency.

Among those hospitalized on Wednesday, one person died, four remained in critical condition, and 18 were in serious condition in Tokyo Metropolis, which has a population of 14 million.

Several cities in central Japan experienced temperatures exceeding 40 degrees Celsius this week, a phenomenon dubbed “Kokushobi” by the Japan Meteorological Agency, a new term translating to “extreme heat day.”

According to scientists, climate change driven by human activity is increasing the frequency and intensity of severe heatwaves in Japan and other regions.

Last year, the country experienced its hottest summer in history, with Japan’s all-time highest temperature recorded at 41.8 degrees Celsius on August 5, 2025, in the city of Isesaki, north of Tokyo.