That broke the previous record of 105.6 degrees set in August 2007.
A week of sweltering conditions sent almost 10,000 people to hospitals by ambulance across Japan, suffering from heat-related problems. Officials said at least 19 people died of heatstroke.
Air conditioning use strained the country’s power grids since Japan shut down its nuclear reactors in the wake of the tsunami-related Fukushima nuclear disaster two years ago.
Meanwhile, nearby China has experienced its hottest summer since 1961, according to the country’s National Meteorological Center.
The official Xinhua news agency reports extreme heat since July 1 has resulted in at least 40 deaths in southern China, while more than 10 people died from heatstroke to the north in the financial hub of Shanghai alone during the period.
Authorities have for the first time declared the heat to be a second-level weather emergency, a designation normally reserved for typhoons and floods.
The World Meteorological Organization says that heat is the greatest killer of all weather phenomena, but it can take weeks after cooler weather returns to collect a full tally of heat-related fatalities.