Sizzling temperatures continued across a broad swath of Japan on Tuesday, with the mercury topping 37 degrees Celsius in Tokyo, ahead of an expected easing of the heat for the rest of the week from Wednesday.

The government issued heatstroke alerts in 23 of the nation¡¯s 47 prefectures Tuesday, affecting tens of millions of people, but the figure was down from the 32 prefectural alerts a day earlier.

In central Tokyo, the temperature rose at a fast pace from the morning, rising above 30 C just after 6 a.m., marking only the sixth time in the past 20 years that temperatures of 30 C or higher were observed by 7 a.m. in July in the area, the Japan Weather Association said.

Meanwhile, the temperature rose to 39 C in Kuwana, Mie Prefecture, 38.8 C in Koshigaya, Saitama Prefecture, and 38.5 C in the town of Yorii, also in Saitama.

This week has seen three straight so-called extremely hot days, where the temperature hits 35 C or higher, recorded at scores of locations across the country. This included 163 locations on Tuesday, a day after the mercury hit the threshold in 195 locations, setting a high for the year for the second straight day.

The weather agency said a strengthening high pressure system over the Pacific was behind the heat wave. But temperatures are forecast to ease from Wednesday, with rain expected in the Tohoku region through Thursday.

People have been urged to take precautions to avoid heatstroke, including using air conditioners and drinking water regularly ¡ª even when not thirsty ¡ª amid the dangerously high temperatures.

The government said Tuesday that more than 3,900 people nationwide had been taken to hospitals due to heatstroke in the week ending July 9 ¡ª a higher number than usual, NHK reported.

¡°Although fewer than the same period last year, when the number of cases reached a record high, the number is still very high compared with previous years,¡± internal affairs and communications minister Takeaki Matsumoto told a news conference.

Japan recorded its highest temperature ever ¡ª 41.1 C ¡ª in 2018 in Kumagaya, Saitama Prefecture, a figure that was matched in 2020 in Hamamatsu, Shizuoka Prefecture.