Faisal Mahmud
21 July 2026•Update: 21 July 2026
Three cities in central Japan saw temperatures of 40C (104F) or higher on Tuesday, marking the country's first officially designated "kokushobi," or "cruelly hot day," since the Japan Meteorological Agency introduced the new heat warning category earlier this year, according to Kyodo News.
Tajimi and Gujo in the Gifu Prefecture saw temperatures of 40.3C (104.5F) and 40.0C (104F) respectively, while Toyoda in the neighboring Aichi Prefecture reached 40.1C (104.2F), the agency said
The term "kokushobi," introduced in April, applies to days when temperatures reach at least 40C (104F) and is intended to strengthen public awareness of life-threatening heat conditions.
The weather agency said a strong high-pressure system covering much of the Japanese archipelago since Sunday has warmed both surface and upper-level air, driving temperatures sharply higher.
As of mid-afternoon, 731 of Japan's 914 weather observation points had recorded maximum temperatures of 30C (86F) or above. Of those, 272 were classified as "moshobi," or "extremely hot days," while the three 40C (104F) readings were separately categorized as "kokushobi."
Other major cities also experienced intense heat, with Nagoya reaching 39.7C (103.5F) and Kumagaya in the Saitama Prefecture hitting 38.6C (101.5F), according to Kyodo.
The meteorological agency warned that dangerously high temperatures are expected to persist across many parts of Japan on Wednesday and urged residents to take precautions against heat-related illnesses, including staying hydrated, avoiding prolonged outdoor exposure, and using air conditioning where possible.