Weather officials in Japan are warning of heatstroke risk and forecast extremely hot weather for much of Japan on Sunday.

The Japan Metrological Agency says that temperatures will rise as a high pressure system covers wide areas from western Japan to northern Japan.

By noon, the mercury had hit 37.3 degrees Celsius in Hamamatsu City in Shizuoka Prefecture, and, 37.2 in Minokamo City in Gifu Prefecture.

A daytime high of 38 is expected for Nagoya City in Aichi Prefecture, Gifu City and Totsukawa Village in Nara Prefecture.

The meteorological agency and the Environment Ministry have issued heatstroke alerts for 31 of 47 prefectures between the Kanto-Koshin and Kyushu regions.

Many people have developed heatstroke as the severe hot weather continues to grip Japan. Extreme cases have resulted in Deaths.

People are advised to avoid unnecessary outings and exercise, use air conditioners appropriately, and to consume adequate water and salt.