Introduction to Heat Waves
The first big heat wave of 2025 has arrived, coinciding with the official start of summer. More than 40 million people in the U.S. were under heat alerts Friday, according to the National Weather Service. Temperatures in the Midwest are expected to crest well into the 90s Fahrenheit (30s Celsius) this weekend. Triple-digit highs could pop up in New York, Philadelphia, Washington and Denver. The peak will likely hit the East Coast early next week.
Climate Change and Heat Waves
Climate change has been exacerbating heat waves, and the problem isn’t going away any time soon. An increasingly hot planet — due largely to burning fossil fuels such as coal, oil and natural gas — means already hot regions are getting worse. Heat doesn’t just mean canceled events. It also poses a health risk, especially for children, older people and those with certain health conditions.
Understanding Heat Danger
When does heat become dangerous?
The answer depends 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.
By CALEIGH WELLS and MELINA WALLING
Just based on heat index, NOAA has a chart that calculates how dangerous prolonged exposure can be. For example, a day where temperatures reach 96 degree F (36 degrees C) and 45% humidity would fall into the “danger” category for prolonged exposure or strenuous activity.
Staying Cool
How to cool down
Overnight lows can be a particularly dangerous part of a heat wave, said Ashley Ward, director of the Heat Policy Innovation Hub at Duke University.
FILE – Mirabelle Demske, second from left, uses a portable electric fan to cool off her friends Faith Hamzy, center, and Annie Sayre, second from right, June 20, 2024, at YMCA Camp Kern in Oregonia, Ohio. (AP Photo/Joshua A. Bickel, File)
“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.
Ward’s answer: Find air conditioning. That might be at home, but she said census data overcounts how many people have 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 a fan.
If you don’t have air conditioning, find public places that do, including movie theaters, malls and libraries. Some communities set up cooling centers.
Depending on where you live, the Low-Income Home Energy Assistance Program can help you buy a window air conditioning unit, according to the National Council on Aging. Some local nonprofits and civic organizations can also help you access one if cost is a burden.
Workplace Protections
Know your rights if you work outside
Knowing what workplace protections you have is important. But there are no federal heat rules to protect workers in the United States.
Some states have them, including Washington, Oregon, California, Nevada, Colorado, Minnesota and Maryland, according to the National Resources Defense Council. Other states don’t have any.
If your state has work rules, try to learn them — though there are still challenges to ensuring regulations are actually enforced, said Bharat Venkat, director of the University of California, Los Angeles Heat Lab.
Heat Illness Symptoms
Knowing heat illness symptoms
Heat illness symptoms can vary by person, Venkat said. Medications or underlying conditions can also make it harder to regulate body temperature or notice you’re getting too hot.
Early trouble signs include heavy sweating, muscle cramps and headache. That’s when you stop what you’re doing and cool yourself off — for example, by splashing yourself with cold water or finding an air conditioned space.
As heat exhaustion sets in, new symptoms arrive, including faster heart rate and dizziness. Next comes heat stroke, which can include confusion, slurred words and fainting. Ward said that’s when to call 911.
“Don’t be embarrassed to call 911 or go to urgent care when you think you might have overdone it in the heat,” he said.
Conclusion
Heat waves pose significant health risks, especially for vulnerable populations. Understanding the dangers of heat and taking steps to stay cool are crucial for preventing heat-related illnesses. By finding ways to cool down, knowing your rights if you work outside, and recognizing heat illness symptoms, you can protect yourself and your loved ones from the dangers of heat waves.
FAQs
Q: What is the wet bulb globe temperature (WBGT)?
A: The WBGT is a measure of heat that includes temperature, humidity, cloud cover, and wind.
Q: How can I stay cool without air conditioning?
A: You can stay cool without air conditioning by using fans, evaporative coolers, or finding public places with air conditioning.
Q: What are the symptoms of heat illness?
A: Heat illness symptoms include heavy sweating, muscle cramps, headache, faster heart rate, dizziness, confusion, slurred words, and fainting.
Q: When should I call 911 for heat-related illnesses?
A: You should call 911 if you or someone you know is experiencing heat stroke, which can include confusion, slurred words, and fainting.
