The Japan Meteorological Agency (JMA) said temperatures of 38 degrees centigrade or higher are forecast in Kanto, Tokai, Kansai and Kyushu regions, while the mercury is expected to hit 39 degrees in the western prefectures of Kyoto and Oita.

Temperatures are likely to rise further in the afternoon, with daytime highs reaching 39 degrees in Kyoto City and 36 degrees in central Tokyo, said the JMA.

The officials warned that risks of developing heatstroke are extremely high, with 40 prefectures, out of the total 47, having been put on the alert, and called on people to be fully vigilant of the intense heat.

(With UNI inputs)