A city in eastern Japan logged the country's highest temperature for a June day on Saturday, rising above 40 Celsius, the Meteorological Agency said.

The heat wave, which the agency expects to persist throughout the summer, came as the government called on households and businesses to save electricity to avoid a possible power crunch until September.

A weather station recorded a temperature of 40.2 Celsius (104.36 Fahrenheit) on Saturday afternoon, in Isesaki, Gunma Prefecture, about 85 kilometers (53 miles) northwest of Tokyo, according to the agency.