The Washington PostDemocracy Dies in Darkness

Record heat wave cooks Japan, straining power grid

A man uses a fan while traveling on a train Monday in Tokyo. (Hiro Komae/AP)

Nearly 5,000 people have been hospitalized amid one of the severest heat waves Japan has seen in over a century, with 37 million people in and around Tokyo told to conserve electricity in response to record-breaking temperatures that are straining the power grid.

According to the country’s Fire and Disaster Management Agency, the number of people sent to hospitals for heatstroke and heat exhaustion is four times higher than during the same window last year, Japan’s Kyodo News reported.

On Monday, Japan’s Meteorological Agency announced the end of the rainy season in Tokyo and neighboring areas in eastern and central Japan, marking the earliest declaration since data became available in 1951, according to Kyodo News. Strong high pressure has controlled Japan’s weather since the weekend and is expected to do so for an additional week — perhaps longer.

The rainy season, which typically begins in June and ends in mid-July, was three weeks shorter than average this year — lasting only 21 days. Because of unusually dry conditions, high temperatures have skyrocketed to an average of 95 degrees. The high in the city of Isesaki, northwest of Tokyo, twice soared to 104 degrees — the highest temperature since modern records began in 1875.

“Tokyo had highs of over 35℃ (95F) for four days in a row, making it the first time on record for June,” meteorologist Sayaka Mori said Tuesday on Twitter. More than 550 monthly records have been broken across Japan.

Japan tops 104 degrees for first time in June amid record heat wave

In its first-ever power supply advisory, the Japanese government called on businesses and households to reduce their energy usage from 3 to 6 p.m. on some days. Workers in the Tokyo metropolitan government have been advised to work in the dark. At supermarkets across the country, lights were switched off in freezers. Electrical appliances at homeware stores have been unplugged.

On Thursday, technical problems briefly took offline a thermal power plant in Fukushima prefecture, in Japan’s northeast, Kyodo News reported.. The shutdown occurred as temperatures in Tokyo climbed to nearly 98 degrees.

Japan has grappled with power shortages since March, when an earthquake in the northeast shut down some of the country’s nuclear power plants. But demand for energy is at its highest since 2011, when Japan was also hit by a record-breaking earthquake. The Economy Ministry warned that the discrepancy between supply and demand is “severe.”

Russia’s invasion of Ukraine has also caused energy prices to rise, leaving government leaders around the world in difficult positions. Japan is not the only country to record unusually high temperatures: Spain, India, Algeria, Finland, Iran and Italy have also seen scorching heat.

To minimize energy costs while also conserving power, Japanese Prime Minister Fumio Kishida announced a rewards system to encourage households to reduce their energy usage.

The government said Friday that it will distribute “points” worth 2,000 yen (about $15) to households if they take part in a nationwide “power-saving program,” prompting outrage on social media as residents grow increasingly frustrated with the government’s mixed messaging. In recent days, officials have also encouraged the use of air conditioning to avoid heatstroke.

A quarter of the country’s population is elderly, at greater risk of suffering severe health consequences because of the extreme heat.

The heat wave is also affecting rivers and dams across the country. The Sameura Dam’s reservoir is at 34.9 percent of capacity, less than half its typical level this time of year. There are worries it will dry up in July.

Although Japan relaxed its outdoor mask mandate for the pandemic in mid-May, many residents are still choosing to wear face coverings outside. The Health Ministry, in response, is broadcasting commercials and distributing leaflets to encourage people to take off their masks while commuting, walking and exercising. The ministry also launched a social media campaign with the hashtag #letstakeoffyourmasks to increase public awareness about heat stroke prevention.

The La Niña weather pattern is a likely major factor in the persistent heat. It helps shift the jet stream and the high pressure typical in the Pacific to the north, leaving Japan in a region at risk for heat waves because of expanding heat domes.

Tsui and Livingston reported from Washington, and Inuma reported from Tokyo.

This story has been updated to attribute to Kyodo News a reported increase in heatstrokes in Japan, the earliest end to Japan’s rainy season since 1951 and technical problems that briefly took a thermal power plant in Fukushima prefecture offline.