Japanese weather officials are forecasting temperatures above 38 degrees Celsius for some parts of the country. They are urging people to be on the alert for heat stroke.
The Meteorological Agency says sweltering weather continued in many parts of Japan on Monday. A daytime high of 38.6 degrees, which was the highest of the season, was recorded in the city of Tajimi, Gifu Prefecture.
Temperatures of 35 degrees or higher were recorded at 177 observation points in the country's network of 921 locations. That was also the highest number of the season.
The agency says the intense heat will likely continue on Tuesday in wide areas from western and eastern Japan through the northeastern Tohoku region.
A daytime high of 38 degrees is forecast in the cities of Fukushima, Maebashi and Kumagaya, and 37 degrees is predicted in central Tokyo.
In the past few days a number of people have been rushed to hospital for possible heatstroke.
People are advised to drink water frequently, avoid direct sunlight outdoors, and use air-conditioning indoors.