June 14, 2022

Heat Index Is Real, People Didn't Survive Before A/C, And Other Heat Wave FAQs, Answered

Q: How long is it going to stay hot?

A: As you can tell by the dramatic top image of a thermometer in the sunshine, a mainstay of lazy hot weather coverage, this heat wave isn't going anywhere.

Some of us might get a brief break this weekend, but the heat is going to build back even hotter next week. 100s are possible into the Mid-Atlantic.

Source: Tropical Tidbits

An upper-level low will swing across Ontario and Quebec later this week, sending a surge of (relatively) cooler air sinking down over the eastern United States. It'll be comfortable in the Northeast, but temperatures will only fall down into the upper 80s and low 90s in the southeastern states.

Meanwhile, a newer, stronger ridge will build in behind that upper-level low, allowing high temperatures in the 100s to spill into the northern Plains and Upper Midwest. That ridge will spread east through the weekend, reaching the eastern states by Sunday and Monday with round two of this prolonged heat event.

The heat index is going to make those brutal temperatures feel even hotter. The prolonged nature of this heat event is really dangerous for vulnerable communities. 

Q: The heat index is a ratings ploy to make it sound hotter than it really is!

A: The heat index is real. Your body cools off through evaporative cooling. Sweat evaporating from your skin helps to regular your body temperature when it's hot outside. Humidity interferes with this process.

When it's both hot and humid outside, your body has to struggle to maintain a healthy body temperature. If the dew point is 72°F—which is Florida-esque tropical mugginess—and the air temperature is 95°F, the heat index is 104°F, meaning that your body is feeling the same strain on that muggy 95°F day as it would if it were actually 104°F.

The higher the heat index, the more stress your body endures in the heat. It's a real thing despite what some hipster hot-take havers want to argue otherwise. Test it at your own peril.

Q: Just open the windows and you'll be fine.

A: Opening the windows and switching on fans can help with air circulation, but it all comes back to your body's struggle to cool off when it's both hot and humid.

Keeping the windows open and fans going doesn't actually lower the temperature. It feels cooler because it speeds up the evaporation of your sweat—a process that's disrupted by muggy temperatures.

The true danger is that a heat wave's effects compound with each day of excessive temperatures and humidity. Homes don't have a chance to cool down as one sweltering day bleeds into a stifling night. The stress grows on vulnerable populations with each day of a heat wave, regardless of whether you've got the windows open and a fan cranking.

Q: This is no big deal. People survived before air conditioning! Why are we so weak today?

A: It's called survivorship bias. Lots and lots of people died before air conditioning as a direct result of not having air conditioning.

It's sort of like the folks who scream "why do we need to coddle kids with all these safety features, I grew up just fine!" Sure, you may have turned out okay! But cemeteries are too full of too many little kids who, it turns out, couldn't get by without car seats or vaccines or wall-fastened dressers or unleaded paint on the windowsill. 

Even with air conditioning all over the place today, heat is still the leading weather-related cause of death in the United States. One bad heat wave can kill hundreds of people, a higher toll than years and years of tragic tornadoes combined. Last year's awful heat wave in the Pacific Northwest was Washington's deadliest weather disaster on record, and it killed nearly 600 people up in British Columbia.

Lots of people died before air conditioning. Lots of people still die without air conditioning. Consider yourself fortunate if you don't have to worry about that.

Q: Dry heat is better than a humid heat.

A: If the humidity makes your body work harder, wouldn't that mean a dry heat is better for you than a humid heat? Not necessarily.

An actual air temperature of 110°F with very little humidity in the air still makes your body work very hard to cool itself off. In fact, you can sweat too efficiently in a dry heat, potentially leading to faster dehydration and heat-related illnesses. 

Q: Why is every piece of hot weather advice so condescending?

A: Television meteorologists and online weather blatherers like me are very aware of how condescending it sounds to say "drink water and stay in the shade" to an audience that's almost entirely grown adults.

It's really, really easy to accidentally overdo it. I walk 5 miles every morning. I get cranky if I have to use the treadmill. But, even doing what I do, I have to consciously remember that the hot weather will knock me flat if I push it too hard. "I'm fine," right up until I'm half a mile from home with an empty water bottle and growing leg cramps.

Hearing safety advice over and over is annoying, but it works. It's worth if it one construction site calls it a day to keep its workers from getting sick, or if the sweet old lady down the street decides to do her power walk on the treadmill instead of pushing it in the hot sun.

Q: I'm not thirsty, so I don't need water.

A: Dehydration sneaks up on you. It's one of those things that's better to stave off than try to correct once it's taking a toll you.

Q: I'm healthy. I'm built for the heat. What's the big deal?

A: While the elderly, folks who suffer from medical issues, outdoor workers, and children are the most vulnerable to heat-related illnesses, it can happen to anyone.

Heat is the deadliest form of extreme weather and it's a silent killer to boot. To put it bluntly: someone dying alone in their sweltering apartment doesn't make as good of a headline as someone dying in a tornado, so it doesn't get much attention. 

Q: When will it cool off?

A: Probably in the fall.

Q: This article format is annoying. What gives?

A: It's a riff on this post from 2016. Meh. It's hard to be funny about a heat wave. It's strange—people lose their minds over a snowstorm like the world is ending, but they'll downplay the extreme dangers of heat even though it claims a toll many magnitudes higher than even the worst blizzard. Go figure.

You can follow me on Twitter or send me an email.

Please consider subscribing to my Patreon. Your support helps me write engaging, hype-free weather coverage—no fretting over ad revenue, no chasing viral clicks. Just the weather.


Previous Post
Next Post

I graduated from the University of South Alabama in 2014 with a degree in political science and a minor in meteorology. I contribute to The Weather Network as a digital writer, and I've written for Forbes, the Washington Post's Capital Weather Gang, Popular Science, Mental Floss, and Gawker's The Vane. My latest book, The Skies Above, is now available. My first book, The Extreme Weather Survival Manual, arrived in October 2015.