Is the U.S. Getting Hot… or Not?

Written by Dr. Matthew Wielicki on August 29, 2025. Posted in Current News

If more CO2 really equals more deadly heat, why are America’s hottest days stuck in the Dust Bowl era while alarmists hype airport thermometers blasted by jet airliners?

We’re told there’s a simple rule. More CO2 means more heat.

If that rule is true, then the steady rise in CO2, including the biggest jump on record during the 2020s, must give us a steady temperature rise.

That fable is the engine that keeps the money moving.

Agencies, universities, media partners, and climate nonprofits all depend on a constant sense of emergency. If the public ever sees the trend as complicated or mixed, the crisis fades and so do budgets. I have written about that incentive structure before.

The climate industrial complex – agencies, universities, media, and nonprofits – thrives on perpetual panic. Admit the US has fewer scorching days despite record CO2 spikes, and their trillion-dollar budgets evaporate.

The basic ‘greenhouse’ idea is that CO2 slows how fast the planet can cool to space. But the step from that simple idea to the claim that every place must see steadily rising daytime heat is where the story runs into the observations. I have shown that in the long record of Earth, there are cases where ice advanced when CO2 was high.

In Earth’s deep history, CO2 and heat don’t move in lockstep.

The Andean-Saharan glaciation froze the planet with CO2 levels 10x today’s.

As the PNAS figure above (overlaid with warm/cool periods) shows, high CO2 often meant ice ages – thanks to feedbacks like ocean outgassing that flip the causation script.

Today’s ‘record’ CO2 jumps (3.6 ppm in 2025 alone, the second largest May-May increase in the 67-year Mauna Loa record) should be scorching us, but they’re not, because CO2 follows temperature, it does not drive it.

You do not need to accept any of that to follow the argument here. Let us look only at measurements inside the United States. Reporters and governmental institutions often say the country is getting hotter.

https://www.yahoo.com/news/summer-2025-forecast-calls-overwhelmingly

https://www.noaa.gov/news/us-sweltered-through-its-4th-hottest-summer-on-record

At the same time, the National Climate Assessment shows fewer hot days at or above 95°F across much of the country. The Environmental Protection Agency’s heat wave index shows the worst American heat waves in the 1930s.

A reconstruction, by Chris Martz, of very hot day counts from the historical station network shows the same story, with a peak around the middle of the last century and smaller values in many recent decades.

Yet the national average temperature is higher today than it was fifty years ago. That seems contradictory until you look at what has changed. Nights have warmed.

Think about what an average means. If you combine a daytime high and a nighttime low, you get a daily mean. If nights creep up while days stay about the same, the mean rises even if you are not getting more brutal afternoons.

The maps in the National Climate Assessment tell that exact story. The panel on warm nights shows increases almost everywhere. The panel on hot days does not.

NOAA’s own maps that separate summer minimums from summer maximums show broad increases in minimums and much weaker changes in maximums, with some regions showing flat or slightly lower daytime highs over long records.

In plain words, the country has fewer freezes and warmer nights. That pushes up the average.

Why would nights warm faster than days? Cities and suburbs hold heat. Concrete, brick, and asphalt absorb energy during the day and release it after sunset. Buildings block wind and reduce ventilation.

Waste heat from traffic, air conditioners, and even aircraft adds to the mix. These effects raise minimum temperatures far more than they raise the hottest part of the afternoon. This is the urban heat island effect.

It is strongest exactly where most thermometers are located and it increases as development grows out around once rural stations. I have written at length about station siting and land use changes.

Once you see the role of nights, a lot of recent messaging makes sense. When the data for scorching afternoons do not cooperate, communicators reach for new metrics that have very short histories.

They lean on feels like numbers, wet bulb thresholds, and model products that did not exist during the Dust Bowl era. Those tools may have uses, but they cannot be honestly compared to the 1930’s.

Meanwhile, some high-profile records come from sensors placed in bad locations. I covered the Tampa airport episode where a thermometer only a short distance from jet exhaust helped produce a headline-grabbing spike.

If you have wondered how we can have fewer very hot days in many regions while the national average moves up, that is the answer. Warm nights and fewer cold days lift the mean.

That has consequences for energy demand and agriculture, but it is not the same thing as a surge in deadly afternoon extremes.

The observations inside the United States do not show a nationwide rise in the most intense hot afternoons.

Even the National Climate Assessment admits as much in its own figures, yet governments and the media continue to tell us the Earth has never been warmer.

See more here substack.com

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