How to stay cool and safe in a heat wave, even without air conditioning

By — Caleigh Wells, Associated Press Caleigh Wells, Associated Press By — Melina Walling, Associated Press Melina Walling, Associated Press Leave your feedback Share Copy URL https://www.pbs.org/newshour/health/how-to-stay-cool-and-safe-in-a-heat-wave-even-without-air-conditioning Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter How to stay cool and safe in a heat wave, even without air conditioning Health Jun 30, 2026 4:02 PM EDT Heat can be dangerous, but health experts say there are ways to manage the threat. Scorching temperatures, especially combined with high humidity, pose risks particularly for children, older people and those with certain health conditions. Anyone can suffer from heat-related illness. READ MORE: Sweltering Midwest heat cancels outdoor plans as cooling centers open and the East braces Climate change is also exacerbating heat waves and heat stress. So here are some tips to stay safe: When heat becomes dangerous Dangers posed by hot weather depend on more than the temperature. The most detailed measurement is called the wet bulb globe temperature (WBGT), which includes temperature, humidity, cloud cover and wind. The heat index, which measures temperature and humidity, is less descriptive but easier to find on weather apps. Both explain why a shaded soccer field on a 90 degree F day (32 degree C) in arid Phoenix may be less risky than an exposed park on an 80 degree F (27 degree C) day in soupy Little Rock. Grow your mind Subscribe to our Science Newsletter to explore the wide worlds of science, health and technology. Just based on heat index, NOAA has a chart that calculates how dangerous prolonged exposure can be. For example, a day in which temperatures reach 96 degree F (36 degrees C) and 45% humidity would fall into the "danger" category for prolonged exposure or strenuous activity. The WBGT threshold isn't exact, but recent research suggests that even some young, healthy people can't endure hours of exposure to high heat and humidity. How to cool down Overnight temperatures can be a particularly dangerous part of a heat wave, said Ashley Ward, director of the Heat Policy Innovation Hub at Duke University. "Your body needs a reprieve," she said. "You don't get that overnight, we start the next day at a deficit." Heat can worsen labor productivity and lead to more visits to the emergency room. "When we have overnight temperatures that don't drop below 75 degrees" F (24 degrees C), she said, "you start to see some pretty extraordinary outcomes with respect to heat illness and heat stroke, and even mortality." Ward said air conditioning can help, but she acknowledged that not everyone has access. If you can't afford to cool the whole house, Ward said, create a "cool corner" and sleep there, so your body is prepared to tackle the next day. Evaporative or "swamp" coolers can help in dry heat, but they increase humidity and can make it more difficult to cool down. In humid places, just use