Climate Change

The New York Times Says Heat Waves Are Getting Worse. The National Climate Assessment Disagrees.

At least in the lower 48 states.


Americans east of the Rockies are sweltering as daytime temperatures soar toward 100 degrees or more. It is now customary for journalists covering big weather events to speculate on how man-made climate change may be affecting them, and the current heat wave is no exception. Take this headline in The New York Times: "Heat Waves in the Age of Climate Change: Longer, More Frequent and More Dangerous."

As evidence, the Times cites the U.S. Global Change Research Program, reporting that "since the 1960s the average number of heat waves—defined as two or more consecutive days where daily lows exceeded historical July and August temperatures—in 50 major American cities has tripled." That is indeed what the numbers show. But it seems odd to highlight the trend in daily low temperatures rather than daily high temperatures.

As it happens, chapter six of 2017's Fourth National Climate Assessment reports that heat waves measured as high daily temperatures are becoming less common in the contiguous U.S., not more frequent.

Here, from the report, are the "observed changes in the coldest and warmest daily temperatures (°F) of the year for each National Climate Assessment region in the contiguous United States." The "changes," it explains, "are the difference between the average for present-day (1986–2016) and the average for the first half of the last century (1901–1960)."

Hot enough for you?

And here is the Heat Wave Magnitude Index, which shows the maximum magnitude of a year's heat waves. (The report defines a heat wave as a period of at least three consecutive days where the maximum temperature is above the appropriate threshold.)


The maps below, from the Fourth Assessment, illustrate the trends in the warmest (generally daytime) and coldest (generally nighttime) temperatures in the contiguous U.S.:

Cooler East Coast?


Warming in the West?

According to the Intergovernmental Panel on Climate Change, climate models tend to significantly underestimate the decrease in the diurnal temperature range—that is, the difference between minimum and maximum daily temperatures—over the last 50 years. The panel's latest report notes that there is "medium confidence" that "the length and frequency of warm spells, including heat waves, has increased since the middle of the 20th century" around the world. Medium confidence means there is about a 50 percent chance of the finding being correct. (The report does deem it "likely that heatwave frequency has increased during this period in large parts of Europe, Asia and Australia.")

Heat wave trends aside, the Fourth National Climate Assessment reports that "the annual average temperature over the contiguous United States has increased by 1.2°F" if you compare the period of 1986–2016 to that of 1901–1960. Outside the lower 48 states, Alaska's average winter and summer temperatures have increased since 1950 by 7°F and 2.6°F, respectively.

Big tip of the hat to the University of Colorado's invaluable Roger Pielke Jr.

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  1. without arguing the stats of hi v low temp, it is pretty well understood that as mean temp increases we will have a cascade of unpredictable events.

    it may not get 108 in dallas, but if it doesn’t cool down below 78 the entire plant ecology is affected.

    1. it is pretty well understood that as mean temp increases we will have a cascade of unpredictable events

      No, it’s not. It is pretty well assumed that if mean temp increases rapidly (i.e. 3 degrees Celsius over 100 years) that we may have a cascade of unpredictable events.

      1. No mean temperature increases should be allowed.

        Only nice temperature increases.

    2. tk: Don’t know about “unpredictable,” but the Plant Hardiness Zones are indeed shifting north.

      1. Is Pielke really the best you can do ?

        The most serious players on climatic bracket creep are the reinsurance majors, and their accountants are running scared

      2. Like the article above, plant hardiness zones are measures of the coldest temperature, not the highest.

      3. The zones have generally moved Northward since the end of Little Ice Age, and certainly since the last glaciation.

        This is not news.

    3. The majority of the warming record occurs during winter time. The warming measured on average is generally contained on two areas, warmer winters and warmer morning temps, ie earth isnt cooling off as quickly at night. The latter is mostly due to urban encroachment on monitoring stations. Ever wonder why news agencies report from the airport sites? 50 years ago most airports weren’t nearly as surrounded as they are now. Airports also put more and more runways, have hitter and more jet engines around sites, etc. More asphalt and structures reduce evening cooling.

      A paper dome about 5 years ago showed well suited stations had a warming rate under half of stations near population centers. Most of the highs you hear about in the media are from urban sites.

      1. I’m intrigued by this paper dome idea of yours, and think it may just save the earth

        1. I too am intrigued by the paper dome. Would it be made from recycled material or from sustainably sourced pulp? What are the projected costs?

      2. Most of the highs you hear about in the media are from urban sites.

        Exactly. Heat saturated asphalt and concrete will reliably give you 1 or maybe even 2 degrees difference, especially at night. There are so many ways to massage results to give you the results you need to keep your funding so your benefactors can keep pushing “STUDIES HAVE SHOWN” directives to their co-conspirators in media.

    4. re: “it is pretty well understood that as mean temp increases…”

      No, actually it is not. Or more accurately, the effects of temperature are quite well-understood – and not at all like the results that you state in your comment. Research Growing Degree Days for more.

      The short version is that the vast majority of temperate-range plant tissues do not really start growing until temperatures reach about 50F for a good part of the day, their growth rate is about linearly correlated with temperature between 50F and 85F and above 85F, the growth rate maxes out. Until you get to near-combustion-levels, the growth rate never inverts. Plants do just as well at 108F as they do at 87F.

      1. Plants do just as well at 108F as they do at 87F.

        Provided sufficient water. Not to disagree with your overall point but, depending on the plant/crop, drought is tolerated better at lower temperatures.

        1. Actually, the biggest factor affecting drought tolerance in most plants isn’t temperature, it’s C02. With higher levels of C02 the pores on leaves, that allow airflow for photosynthesis during the day and respiration at night, can contract and the plants loose less water to the air over time at any temperature.

      2. The problem with an increase in average temperature, you shift the curve to the hot end. At some point you start getting longer, hotter crop killing heatwaves.

        1. I wonder how much exaggeration has gone into reporting on crop damage and reduced yields, because more apparent lost revenue means more sudsidies and bail-outs, which is seemingly what a large part of the agricultural industry is sustained by. Another welfare trap.

          1. (citations can be found in a publication by the office for some sort of information about things)

            1. Because agencies which depend on inflating a crisis for increased funding would NEVER shade the numbers….. likewise researchers lapping up government grants….. like say, Michael Mann / NASA / East Anglia.

              Sorry, your trust fund has a negative balance.

          2. “I wonder how much exaggeration has gone into reporting on crop damage and reduced yields”

            I don’t think we are at a point where heat waves are killing off crops in any quantity. The point I’m making, and it’s a little counter-intuitive, is that a slight increase in AVERAGE temperature means means more days that are hotter. Heat waves! It would be nice if dear mother nature saw to it that temperature increases were more on the cold side of the curve, but that’s not the case.

    5. People have been moving to warmer climates in the South and West for decades. Now the nice warmer weather is moving to them. It’s not a crisis.

      1. Well, if the Blue Mafia-run murder capitals are getting warmer, will that mean the idiots now leaving to escape the hell they created decide to stay put? You know, instead of moving to Texas and screwing that up, too?

        Is it possible to just move Austin to California, like when minor league franchises get shuffled around? There’s been a few moves in TX recently along those lines. Amarillo just got the stupidest-named baseball team ever. Are there any oases of sanity in blue states who could move to fill the void?

        Dear Austin, you are no longer affiliated with the State of Texas and therefore will be moving to California to continue as Usedtobecoolsville. The City of Redding, CA will be moving to the former Austin and continuing as New Better Austin.


        1. I respectfully disagree. As one who spent the better part of thirty years living in or near Redding, CA, the State of Texas would NEVER, in a thousand years, allow Redding to be relocated there! (sarc)

  2. It’s almost as if there was some giant heat sink dampening the temperature extremes.

    1. No, no – the heat sink is just hiding all that heat and letting it build up so that it can suddenly spring on us all at once, because that’s just how Nature works.

      1. Some day the warming monster will rise from the oceans and punish man for his sins!!

        1. Many will know what it is to be roasted in the belly of the Slorg on that day!

          1. Is that what we’re calling SEA SMITH now?

          2. Only the Shubs and Zulls though…

        2. History shows again and again how Nature points out the folly of Man…

          Go go Godzilla!

        3. All the skyscrapers in all the coastal cities will be underwater. I saw it in a chart in the news once.

    2. It’s all run by the walrus mafia.

      1. Parks and Rec?

  3. According to experts like AOC, we have just 12 years left before the planet becomes literally uninhabitable. Only a Democrat-controlled government can save us from the climate apocalypse.

    1. we have just 12 years left



    2. According to Prince Charles we only have 18 months.

      1. That’s what he keeps telling his Mum.

    3. Shouldn’t we forget about free college and Medicare for all then, and pour all our government (lack of) funds into fighting climate change? Is pandering for votes more important than saving the planet?

      1. “Is pandering for votes more important than saving the planet?”

        There is NOTHING more important than pandering for votes!


  5. Tell that to the people on the subway sitting in a pool of ball sweat!

    1. I told her not to sit down there, but she wouldn’t listen to me.

    2. I manspread my ball sweat evenly across the subway car, so it never pools.

  6. Americans east of the Rockies are sweltering as daytime temperatures soar toward 100 degrees or more.

    Oh east of the Rockies. What happens east of the Rockies doesn’t even get me up in the morning.

    BTW, despite dire warnings, the PNW is having a cooler than normal summer. Current temperature outside: 60f.

    1. SF East Bay currently mid-to-high 60s. I could count on one hand the number of days we broke 90 this summer, even inland. Weirdly humid, though (weirdly humid here being >45%).

    2. Excuse me, but in case you didn’t notice the Eastern Time Zone is THE time zone to be in. Everyone who is anyone knows looks at his watch and sees it’s almost 2:23PM right now.

      1. If it’s happening east of the Hudson, it’s happening to America!

    3. When it’s unusually cool the cultists will tell you that weather and climate are two different things.

      When we have storms (weather) it’s because of climate change. Go figure.

      1. It is as if they lack consistency.

    4. A New Englang heat wave is when you can fry an egg on the stone steps of the American Meteorological Society.

      Like today, tomorrow and Sunday.

    5. This never happened when I was a kid, we never saw 100 degree days! Why it was basically Hawaii weather year round. We’re doomed.

  7. Tony will be along after his daily science belief prayers to tell us that he has read enough to know that this article is garbage. Also, the Earth will actually become Venus in another 11 years, killing off even single-celled life in rock 10,000 feet below the surface.

    1. “killing off even single-celled life in rock 10,000 feet below the surface.”

      Didn’t Al Gore say it’s already 1,000,000 degrees down there?

      1. Dunno. I haven’t paid any attention to that worthless blob of hypocritical goo since the times when he served as a bagman for the Chinese government.

    2. He has to get his talking points from Media Matters first. Fucking follower that he is.

  8. Over the past 2,000 years, the average temperature of the Northern Hemisphere has exceeded natural variability (defined as two standard deviations from the pre-1865 mean) three times: 1) the peak of the Medieval Warm Period 2) the nadir of the Little Ice Age and 3) since 1998. Human activities were unlikely to have been the cause of the first two deviations. 70% of the warming since the early 1600’s clearly falls within the range of natural variability.

    And “medium confidence” is fancy way of saying “I don’t know”. If I said for example, “I have medium confidence that the Yankees are going to win the American League east since they lead by 8 games on July 19th,” could anyone reasonably say I “know” the outcome of the division? No they couldn’t.

    1. Human activities were unlikely to have been the cause of the first two deviations.

      So, they were caused by neither humans nor Nature?

      This sounds like a Lovecraft story in the making.

      1. It’s the warming monster. He is one of the Old Ones

        1. Revenge of The Heat Miser?

      2. ….or crab people.

        Crab people…….crab people……….

      3. Forget the boiled crabs- it just broiled a razorback to death:
        Former NFL player Mitch Petrus has died from heatstroke at the age of 32.

        He was working outside at his family’s business in Little Rock, Arkansas when he fell ill on Thursday. He died in hospital that evening.
        Petrus was a lineman for the New York Giants, and part of the Super Bowl 2012 winning side. He joined the New England Patriots later that year.

    2. Multiple science and engineering classes I took used the term ‘epistemological ignorance’ to describe what they’re describing as ‘medium confidence’. You know just enough to boil the problem down into binary outcomes and can make no assertions as to which outcome is more likely. This makes you functionally equivalent, from a statistical perspective, to a fair coin.

      1. yes… ‘medium confidence’ is a way for people who don’t really know much about something to come off as smart to an audience that doesn’t know better. Certainly sounds better than “It could go either way we really have no idea”

        (i make no comment on the state of climate science, i am only addressing the narrow point that ‘medium confidence’ is pretty much a BS term)

        1. I’ll make a comment on the state of climate science:
          I have extra High Confidence that the 11/22 year SunSpot Cycle will continue as earlier predicted for a Confidently High long time.

          I have Very Low Confidence in anything else.

    3. John, re: your medium confidence in the Yankees winning the AL East …. I think it’s time to pull together some of the keen commentary in this thread. To that end, keep an eye on Yankee pitchers reaching down underneath their belt line, inside their uniforms. If you see that happening more and more it means they’ve discovered that a guy can change trajectory on his fastball by using ball sweat on his fingers. Assuming other teams do not catch on to this as quickly as the Yanks, hotter weather in the Northeast US could indeed allow you to predict the pennant for New York with “medium-plus” certainty.

  9. Why is this Terraforming project taking so long and costing so much!

    I want my global warming soon rather than decades in the future.

  10. What? The NYT is full of it again?
    NOT news.

  11. WE DIDN’T LISTEN!!!!!


  12. Average American in July: “Sure is hot outside. Hotter than I can remember.*”

    *Average Americans can only remember things 3-6 months in the past.

    1. In recent years one of the leading climate scientists – may have been Michael Mann or James Hansen, but I don’t remember which – commented that if you think you’re noticing the 1.5F rise in global mean temperatures over the last several decades, you are succumbing to hysteria.

      Mann also recently expressed concern that the hysterical lying about Climate Change that is happening constantly in the media is going to cause a backlash. He’s not wrong.

  13. The NYT is just another AGW cheerleader. People of their ilk have shown repeatedly that they feel the ends justify the means and will lie, distort, and ignore facts to further their agenda.

    1. That would be the same NYT who employed a blatant cheerleader for Stalin, one who outright denied the Holodomor, who intentionally deceived America about the genocidal mass-murder of millions of innocents in the name of Communist solidarity.

      That rag is stained with the blood of history. That it’s still considered relevant today is an obscenity.

      I’ll just leave a link to this puke-inducing article:

  14. I know as much about climate science as your average “liberal” knows about Basic Economics; but it’s my impression that summers are getting hotter, or at least feeling hotter, in the Sun Belt City where I live. It may not be the temperatures rising, per se; but we used to get a monsoon-like cloudburst every afternoon or evening, which would cool things off a bit, at least for a few hours. We don’t seem to get these cloudbursts the way we used to. What the reason for that is, I have no idea.

    1. The atmospheric water on the West Coast has been a bit wacky for several years. In the SF East Bay we’ve been able to rely on swamp coolers for as long as we’ve been here (25+ years), but the last two years they haven’t worked because the humidity has routinely topped 50%, which is very uncommon in CA.

      It feels hotter because of the humidity, so of course everyone is making comments about global warming even though the actual temperatures two summers ago were far higher.

      I wouldn’t rule out that this has to do with climate change, but the immediate impact seems more to do with cooler, wetter air coming down from the melting icecaps (as Lovelace predicted it would) than with increasing temperatures in the temperate and tropical zones.

    2. I don’t want to be a jerk…
      But if you live in Atlanta, you’re misremembering.
      I’ve been in Jax the last 2 summers, but prior to that was in Atlanta for 20 years.
      Some summers hotter, some summers wetter, but same weather generally and oft alternating – though for a few years when I was younger there was the drought

  15. I agree that we are experiencing warming, but the fact that the people who scream the loudest about it don’t seem to want to take any meaningful steps to prevent it, such as building more nukes or allowing more natural gas pipelines makes me doubt their predictions. I’m sorry, English majors living in Brooklyn are not climate experts anymore than I am an expert on post-structuralism.
    They pick their data and want to force the rest of us to eat it.

  16. If we’d start praying to the Sun again, we’d be fine.
    Maybe throw in some human sacrifice, just to appease Gaia.

    1. Forget Gaia–
      If you can throw a human sacrifice into the sun, the US Olympics team wants you.

  17. If we outlawed air conditioning everyone would know it is getting hotter. I wish that wasn’t actual serious logic by some in 2019.

  18. The new fad of “Climate Warming”, or oops, “Climate Cooling” or oops, I guess just “Climate Changing” — Is the perfect example of how Hitler gained so many supporters. It is shockingly amazing the strength of group-y supporters one lying deceitful imbecile can build with the right persist-ency and attention.

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  20. Don’t see the politics point.

    Hot and muggy here. We are in this weather thing. So we went out with the dog to the lake. Because you have to do something with him.

    He is a Labrador so built for water. They have these big paws, a tail like a rudder, strong hind legs, you do not need to teach them anything.

    One advice I have for those so worried about climate change. Teach your children how to swim. It is useful and not difficult to learn.

  21. If we outlawed air conditioning everyone would know it is getting hotter. I wish that wasn’t actual serious logic by some in 2019.

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  22. Thanks to Bailey for showing yet another example of NYT’s propaganda for big government, and indifference to truth and their reputation for honesty (I guess they want a reputation as propagandists for the Democrats).

    I’m not surprised most commenters dwell on the AGW arguments, rather than honesty in reporting. But it’s the dishonesty in reporting for more government, that’s led to so much misinformation on the subject. As Mark Twain said, “If you don’t read the newspaper, you are uninformed. If you do read the newspaper, you are misinformed.”

  23. “But it seems odd to highlight the trend in daily low temperatures rather than daily high temperatures.”

    Why does it seem odd?

    It’s actually the daily low that can kill. People can take high temperatures as long as they are followed by the decrease in temperature we experience at night. When that difference is narrowed and people are exposed to constant high temperature without the usual night cooling, then people, especially the old, young and weak, risk death due to overheating and its complications.

    Also, I’m pretty certain that if average temperature increases, then heat waves will also increase, assuming normal bell-like distributions.

    1. But is a heat wave usually defined by the number of days when it doesn’t cool off at night? At least here in the northeast, a heat wave is defined by two or more days in a row when the temperature rises above 90 degrees F.
      But I guess looking at those days when the temperature never dropped below some temperature at night would offer a way to define heat waves, too. Either is probably good. But the point is that, defined one way, the data shows an increase in “heat waves”, defined another (the way most people define it), it doesn’t. Even if one says that both definitions are equally valid, the results are not very compelling.
      Looking for and then using the data sets that confirm one’s desired results is not science, it’s what those acting as advocates do. Lawyers do this as a matter of course and find that they can also act as activists. Scientists who consider themselves to also be activists are fooling themselves; they cannot be both.

    2. This is trueman; you get sophistry or bullshit. He’s got nothing else. If you wish to wate time engaging this POS, help yourself, but expect nothing other than sophistry or bullshit.

  24. I LOVE statistics! They’re so…sciency! Can’t show what you want comparing daily high temperatures? No problem. Just compare rates of the highest low temperatures. Or the average rise in temperatures between two days. Or the mean number of Tuesdays per year when late afternoon “feel-like” temperatures has a net positive difference among the highest modes. Its all good.
    Of course, while the amount of truly bad science that is driven by popular discussions of climate change is astounding, there is plenty of simple, persuasive evidence that CO2 levels have been greatly increasing and plenty of good science to show that GLOBAL temperatures have been increasing and is likely caused by the former. But, since the science that first proposed the dangers of AGW also explained that it’s action would be very difficult to see in everyday weather occurrences, the activist community has decided that science is but a tool in their ongoing quest to save mother earth.

  25. Also, when reading about the weather trends for the USA’s lower 48, bear in mind that it represents 1.5% of the area of the earth. That is, this small part of the world, subject to a unique global environment and having singular form and geography is a really lousy proxy for the globe as a whole.

    1. A good proxy for the whole globe is someplace underwater in the Pacific.

  26. The summer here in Texas is actually cooler than normal since we have not had any days over 100 degrees so far. The humid has been higher which pushes the heat index up but it is July and it is supposed to be hot. The NYT is just using this as another excuse to push the “global warming” narrative. Does the climate change? Yup, every day.

  27. NYC weather:

    3* higher than July average.
    I think what they just SUFFERED THROUGH (!!!!) is what we called a ‘heat wave’ when i lived back east.
    Screw ’em. Tell ’em to turn on the A/C and ignore the ‘climate-change’ twits in their hair shirts.

    1. The proper form is ° == > & d e g ;

  28. […] recent post: “Call It the Trump Heat Wave.” Even if it is not the record (remember the dust-bowl 1930s?), and forgetting the increasing concrete heats the heat (U.S. cement sales rose 3 percent last […]

  29. […] The New York Times Says Heat Waves Are Getting Worse. The National Climate Assessment Disagrees. […]

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