According to the JMA, a dominant high-pressure system is driving up temperatures from western through northern Japan, and the mercury is expected to rise even higher in the afternoons, reports Xinhua news agency.
The city of Koshigaya in Saitama prefecture logged a temperature of 37.5 degrees Celsius before noon, while central Tokyo recorded 35.6 degrees, said the JMA.
Daytime highs of 39 degrees were forecast in Kyoto and 38 degrees in cities such as Osaka, Nagoya and Saitama, it added.
Weather officials warned that the intense heat is expected to continue through next week.
–IANS
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