The wet-bulb theory?

Smartphones have a lot of advantages and disadvantages. Just ask any good divorce attorney. One area in which they excel, however, is with regard to keeping up with the weather.

When this week’s weather forecast popped up, the first thought was — if it’s already going to be 101 this Wednesday and 100 degrees on Thursday, and the seven days after that are all forecast to be in the upper 90s, what kind of a scorching summer are we going to have to endure, pray tell?

Love the Weather Apps

The free weather apps that most of us can download on to our phones (Weather Bug is a good one) are a great way of not only watching out for dangerous weather — extreme heat, cold, violent storms, ice — but to also keep track of past weather patterns, so that we’ll know when something looks out of whack. Not that much can be done to change things, but it’s nice to keep tabs on what’s going on.

For example, if we see a 10-day forecast that looks out of kilter — too hot, too cold — we can take a screen shot and store it with the rest of our photos.

Then, when we see that it’s forecast to be 101 on Wednesday, we can look at screen shots from a year ago, or two, and see that it wasn’t much different. It just feels that way.

Of course, with the advent of air conditioners, which really started to go into widespread use in the 1960s for those who could afford it, there’s not a lot for most of us to complain about anymore.

We go to sleep with the air conditioning on, wake up with it on, walk to our airconditioned car/truck where we text and eat a donut, get out and walk into our air-conditioned office, and the only time we spend any time outside in the 101-degree heat is when we go out and walk the dog.

“Hurry up and do your business.”

The guys who look superhuman are the roofers laying down a new roof with the mercury pegged at 102.

If our hardy ancestors could look at us today, they’d probably say, “What in the world do you possibly have to complain about?”

At least with regard to dealing with South Texas’ heat.

The ones who have it especially rough are those homes in many parts of the Midwest. If anyone has been keeping track of those temps, the mid-80s in southern Wisconsin in mid-May, no, that’s not normal, but that’s what is forecast for this week. In that area of the country, many homes still don’t have AC, because it seldom gets hot enough to warrant the cost.

Like most other weather patterns, though, that’s starting to change as more ice caps continue to melt.

What will it be like in 25 years, 50 years, a hundred years?

No way of knowing.

Extreme heat, extreme cold, neither is good.

Wet Bulb Theory

Have you ever wondered how hot it can get before human beings can no longer tolerate it? In other words, survive?

By the way, according to the National Weather Service out of Brownsville, “an average to hotter-than-average outlook is favored during the May-July 2025 timeframe for Deep South Texas and the Rio Grande Valley.”

Oh, boy.

“Meanwhile, precipitation remains a toss-up across the region. While there will be many dry days through July, there could be bouts of showers and thunderstorms that should keep the precipitation surplus/deficit in balance.”

The wet news is at least a little promising, plus, moving forward, there is optimism for the ag industry and municipalities now that Mexico is keeping up with its water payments to the U.S., which helps. A lot.

Still, here is what scientists say is the max temp for human survivability, but it’s actually based on temperature and humidity, which is the basis for the heat index.

In climate circles, the number is known as the “35 degree wet-bulb temperature theory,” and it goes like this, with the understanding that a healthy adult may survive it up to six hours (don’t worry; not expected anytime soon).

Let’s let Google’s AI (sourced) explain it:

Recent research and long-standing physiological understanding suggest that a wet-bulb temperature of 35°C (95°F) is the theoretical upper limit for human survivability for more than a few hours, even for a healthy, resting individual in the shade with unlimited water.

Wet-bulb temperature essentially measures how effectively the human body can cool itself through sweating. It's the temperature a parcel of air would have if it were cooled to saturation (100% relative humidity) by the evaporation of water into it.

When the wet-bulb temperature reaches 35°C (95 degrees F), the air is so hot and humid that sweat cannot evaporate from the skin.

Without the ability to evaporate sweat, the body cannot shed its internal heat, leading to a rapid rise in core body temperature, hyperthermia, heatstroke, and eventually death.

How does one arrive at a wetbulb temp of 95 degrees Fahrenheit?

At 100% relative humidity, an air temperature of 35°C (95°F) would also be a wet-bulb temperature of 35°C.

At 50% relative humidity, an air temperature of around 46°C (115°F) would yield a wet-bulb temperature of approximately 35°C.

So, there’s still a big difference between 101 degrees and 115 with 50% humidity.

Thankfully.

In June 2023, we ran into this heat wave, starting on the 21st: Wednesday through Saturday, Hidalgo County was forecast to be 107, 104, 102, and 102.

Then over the next five days, the daytime temp fluctuated between 103 and 104.

At the time, forecast temps for Death Valley were cooler.

Last but not least, just so we don’t forget last May (2024), here is an excerpt from a weather story The Advance published May 8th: “The high for today (Wednesday, the 8th) is forecast to be 106 degrees in Hidalgo County? The heat index – 112 degrees.”

So, no, it’s not getting any hotter than the previous two or three years.

It just feels that way because the winter temps bring us back to a sense of normalcy.

Then the summer heat begins. Once again.

No matter, the scorching weather still beats five degrees below zero and having to scrape ice from your front windshield while your fingers grow numb.