Scientific American, 17 June 2025

Hotter Nights, Brought on by Climate Change, Pose More Health Threats

When nights stay hot, more people die, many from cardiovascular problems. But there are simple methods you can use to stay cooler and healthier.

If the summer of 2025 is anything like last year’s, get ready to sweat. July and August of 2024 were among the hottest months on record in the U.S. Phoenix, Ariz., saw daytime temperatures higher than 100 degrees Fahrenheit for more than 100 days. But now temperatures are staying high at night, too, which increases health dangers. When it stays hot after the sun goes down, more people die than typically would. Emergency room visits and hospital admissions go up. Premature births increase. Sleep and mental health suffer. But there are simple and practical methods you can use to stay cooler and healthier, beyond cranking up your expensive air conditioner.