Why it matters: Intense, long-lasting heat waves are one of the most robust signs of global warming, according to numerous scientific studies. This will compound the challenges and costs for countries working to recover from extreme weather.

• The floods earlier this month displaced 1.6 million people.
• Now, tens of thousands have entered hospitals with symptoms of heat stroke and 70 people have died as a result of the heat, according to Kyodo News Agency.

What's next: The heat wave has blanketed the country for two weeks now. Air conditioning remains uncommon in schools and cooler parts of the country, making it difficult for many to find relief.

Go deeper:

• Japan's floods and Earth's third warmest June, per Axios' Andrew Freedman.
• All-time heat records breaking all over the world, from the Washington Post.