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.