Photo/IllutrationRunners jogging in front of the Imperial Palace’s historic Nijubashi bridge in Tokyo’s Chiyoda Ward on Aug. 9 encounter a mirage. The road will be part of the marathon course for the Tokyo Olympics in 2020. (Kazuhiro Nagashima)

Deaths due to heatstroke reached 101 since July 1 in Tokyo’s 23 wards, according to the Tokyo Medical Examiner’s Office.

The tally to Aug. 18 showed that people aged 65 and older accounted for 90 percent of the deaths.

More than 90 percent of all fatalities occurred indoors.

The deceased comprised 53 men and 48 women ranging in age from their 40s to their 90s.

Ninety-one victims were aged 65 or older.

By age group, those in their 70s accounted for the highest number of deaths at 42, followed by 31 people in their 80s. Ten victims were aged 65 or younger.

Twenty-eight people died between 5 a.m. and 5 p.m. and 32 people died between 5 p.m. and 5 a.m.

Of the 94 people who died indoors, 40 were located in a room with an air conditioner installed. But in 38 of the cases, the appliance had not been switched on.

According to the Japan Meteorological Agency, the daily low temperature in central Tokyo was 25 degrees or higher for 24 consecutive days from July 26 to Aug. 18, making it the second-longest hot spell since 1876, when records were first kept.

The agency said daytime temperatures for the next two weeks will be in the lower 30-degree range.

Even if the sweltering heat eases, authorities urged people to take measures against heatstroke.