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Japan Adds 'Kokushobi' for Severely Hot Days Amid Rising Temperatures

4/18/2026

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Summary

Story summary

The Japan Meteorological Agency (JMA) added the term kokushobi, meaning a severely hot day, to its weather lexicon on April 17, 2026.
The decision followed an online survey and expert opinions on rising heat.
Since 1872, there have been 108 days above 40°C, including 41 from 2023 to 2025.
Other terms in use include natsubi for days over 25°C, manatsubi for over 30°C, and moshobi for over 35°C.

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Story summary

The Japan Meteorological Agency (JMA) added the term kokushobi, meaning a severely hot day, to its weather lexicon on April 17, 2026.
The decision followed an online survey and expert opinions on rising heat.
Since 1872, there have been 108 days above 40°C, including 41 from 2023 to 2025.
Other terms in use include natsubi for days over 25°C, manatsubi for over 30°C, and moshobi for over 35°C.