Hot weather can be deadly, but health professionals say there are practical steps you can take to protect yourself and your family.
Extreme temperatures — especially when paired with high humidity — create serious risks, particularly for children, older adults, and people with underlying health conditions. That said, anyone can fall victim to heat-related illness. And with climate change making heat waves more frequent and severe, knowing how to respond has never been more important.
Here’s what you need to know:
The danger from heat isn’t just about the temperature on the thermometer. The most comprehensive measurement is called the wet bulb globe temperature, or WBGT, which factors in temperature, humidity, cloud cover, and wind speed. A simpler but still useful tool is the heat index, which combines temperature and humidity and is available on most weather apps. These measurements explain why a shaded soccer field in arid Phoenix on a 90-degree F (32 degrees C) day might actually be safer than an open park in humid Little Rock on an 80-degree F (27 degrees C) day.
Using the heat index, NOAA provides a chart showing how dangerous extended exposure can become. As an example, a day reaching 96 degrees F (36 degrees C) with 45% humidity would be classified in the “danger” zone for prolonged outdoor activity or strenuous exercise.
Research also shows that even young, healthy individuals can struggle to handle extended exposure to high heat and humidity — making the risk more widespread than many people realize.
Nighttime temperatures during a heat wave can be especially treacherous, according to Ashley Ward, director of the Heat Policy Innovation Hub at Duke University.
“Your body needs a reprieve,” Ward said. “You don’t get that overnight, we start the next day at a deficit.” She added that heat can reduce productivity at work and drive up emergency room visits.
Ward also warned that when nighttime temperatures remain above 75 degrees F (24 degrees C), the consequences become severe. “You start to see some pretty extraordinary outcomes with respect to heat illness and heat stroke, and even mortality,” she said.
While air conditioning is one of the best defenses, Ward acknowledged that not everyone can afford it or has access to it. For those who can’t cool an entire home, she recommends creating a “cool corner” — a single cooler area where you can sleep — so your body can recover overnight and be ready for the next day.
Evaporative or “swamp” coolers can offer relief in dry climates, but they add humidity and may actually make things worse in already-humid conditions. In those cases, a simple fan is a better option.
If you don’t have any home cooling, seek out public spaces with air conditioning — movie theaters, shopping malls, and libraries are all good options. Many communities also set up designated cooling centers during heat emergencies.
Depending on where you live, the Low-Income Home Energy Assistance Program may be able to help you purchase a window air conditioning unit, according to the National Council on Aging. Local nonprofits and civic organizations may offer similar assistance.
Workers should also be aware of what heat protections their state provides. According to the Natural Resources Defense Council, states including Washington, Oregon, California, Nevada, Colorado, Minnesota, and Maryland have workplace heat rules in place — but many states have no protections at all.
Even where rules exist, enforcement can be inconsistent, said Bharat Venkat, director of the Heat Lab at the University of California, Los Angeles. He pointed out that shaded rest areas are sometimes too far away for workers to use without losing pay, and that some management environments make it difficult for workers to speak up. “Most workers don’t actually have control over their time or control over where they work,” Venkat said.
Within those limitations, staying hydrated and keeping your body temperature down are critical. Drink plenty of fluids, wet your clothing, or apply cold water or a cool cloth to your hands, feet, armpits, and neck. A handheld portable fan or a cooling vest can also make a real difference.
If you exercise outdoors, avoid the hottest parts of the day and always bring more water than you think you’ll need.
Heat illness symptoms can look different from person to person, Venkat noted. Medications and pre-existing conditions can also interfere with the body’s ability to regulate temperature or recognize when it’s overheating.
Early warning signs include heavy sweating, muscle cramps, and headache. If these appear, stop what you’re doing immediately and take steps to cool down — splash yourself with cold water or move to an air-conditioned space.
As the condition worsens into heat exhaustion, symptoms such as a rapid heartbeat and dizziness may develop. Heat stroke — the most dangerous stage — can cause confusion, slurred speech, and loss of consciousness. Ward said that’s when you should call 911 without hesitation.
“Don’t be embarrassed to call 911 or go to urgent care when you think you might have overdone it in the heat,” Venkat said.
