The nation entered the dog days of summer Tuesday as temperatures climbed above 40 degrees Celsius in some areas, prompting authorities to issue a heatstroke warning and encourage the removal of face masks in certain situations.
By 3:20 p.m. Tuesday, temperatures had reached 40.5 C in the cities of Isesaki and Kiryu in Gunma Prefecture, the hottest reading so far this year, while the town of Hatoyama in Saitama Prefecture had hit 40.2 C. Municipalities in Gunma, Tochigi, Toyama, Saitama, Fukushima, Tokyo and Ibaraki registered temperatures around 38 C or 39 C.
Even in the cities of Sapporo and Asahikawa in Hokkaido, which is generally cooler than the main island of Honshu, the mercury rose above 30 C. At the opposite end of the country, the tropical city of Naha in Okinawa Prefecture recorded 33 C in daytime temperatures.