Home / Weather / Japan Names Extreme Heat Days 'Kokushobi'
Japan Names Extreme Heat Days 'Kokushobi'
20 Apr
Summary
- Japan's JMA introduced 'Kokushobi' for days over 40C.
- Summer 2025 was Japan's hottest on record, with temperatures soaring.
- Climate crisis fuels extreme heat and impacts global weather patterns.
Japan's Meteorological Agency (JMA) has officially adopted 'Kokushobi,' a term signifying brutally hot weather, for days reaching or exceeding 40 degrees Celsius. This marks the first introduction of a new weather forecast term since 2007, when 'mōshobi' (extremely hot day) was established for temperatures over 35C. The name 'Kokushobi,' translating to 'cruelly hot,' was selected through a public vote.
Summer 2025 was declared Japan's hottest on record, with nationwide average temperatures 2.36C above normal. Record-breaking temperatures of 41.8C were recorded in Isesaki on August 5, significantly higher than the previous year's peak. Scientists attribute this intense heatwave primarily to the ongoing climate crisis, noting the warming of surrounding oceans which exacerbates high temperatures well into autumn and influences weather patterns.
The phenomenon aligns with global trends, as 2025 was the third hottest year globally, and the past three years have been the hottest ever recorded. Experts cite increased greenhouse gas emissions and record-high sea-surface temperatures, influenced by El Niño and climate change, as key factors. This ongoing warming poses significant risks to lives, infrastructure, and economies worldwide, highlighting the urgency of transitioning to renewable energy sources.
