Many parts of Japan had another sweltering day on Thursday, with temperatures rising dangerously close to 40 degrees Celsius in some places. The ongoing heatwave is raising the risk of heatstroke.

Clear skies covered eastern and western Japan on Thursday, driving up temperatures.

The Meteorological Agency says that temperatures of 35 degrees or higher were recorded at 178 locations nationwide.

The mercury rose to nearly 40 degrees in several locations in the Kanto and Tokai regions. They included Hatoyama and Yorii towns in Saitama Prefecture; Isesaki City in Gunma Prefecture; Hamamatsu City in Shizuoka Prefecture; Tajimi City in Gifu Prefecture; and Toyota City in Aichi Prefecture.
The daytime high in central Tokyo reached 36.4 degrees on Thursday. That was the hottest temperature recorded in the city in June since record-keeping began in 1875.

This year's highest temperatures so far were recorded at 289 locations, or about a third of the Meteorological Agency's observation spots across the country.

Temperatures are forecast to remain above 25 degrees in the Kanto and Tokai regions overnight, and it will be another scorching day on Friday.

Nagoya City can expect a high of 40 degrees. Gifu City and Kumagaya City in Saitama Prefecture can expect a high of 39 degrees. A high of 36 degrees is forecast for central Tokyo.

A heatstroke alert has been issued for wide areas of Japan, from Kanto Koshin down to southern Kyushu.

Health officials warn that with temperatures staying so high overnight, there is a heightened risk of people developing heatstroke indoors. They are advising people to stay hydrated by keeping a bottle of water at their bedside and to keep air-conditioners on.

The scorching summer weather has led to an increase in the number of people being taken to hospital with symptoms of heatstroke. There have been frequent reports that elderly people have died from heatstroke.

Officials are asking people to call their elderly relatives to persuade them to appropriately use air-conditioning in their homes, and to avoid going out during the day as much as possible.