The US Blows Hot And Cold

Guest Post by Willis Eschenbach

I got to thinking about the raw unadjusted temperature station data. Despite the many flaws in individual weather stations making up the US Historical Climate Network (USHCN), as revealed by Anthony Watts’ SurfaceStations project, the USHCN is arguably one of the best country networks. So I thought I’d take a look at what it reveals.

The data is available here, with further information about the dataset here. The page says:

UNITED STATES HISTORICAL CLIMATOLOGY NETWORK (USHCN) Daily Dataset M.J. Menne, C.N. Williams, Jr., and R.S. Vose National Climatic Data Center, National Oceanic and Atmospheric Administration

These files comprise CDIAC’s most current version of USHCN daily data.

These appear to be the raw, unhomogenized, unadjusted daily data files. Works for me. I started by looking at the lengths of the various records.

Figure 1. Lengths of the 1,218 USHCN temperature records. The picture shows a “Stevenson Screen”, the enclosure used to protect the instruments from direct sunlight so that they are measuring actual air temperature.

This is good news. 97.4% of the temperature records are longer than 30 years, and 99.7% are longer than 20 years. So I chose to use them all.

Next, I considered the trends of the minimum and maximum temperatures. I purposely did not consider the mean (average) trend, for a simple reason. We experience the daily maximum and minimum temperatures, the warmest and coldest times of the day. But nobody ever experiences an average temperature. It’s a mathematical construct. And I wanted to look at what we actually can sense and feel.

First I considered minimum temperatures. I began by looking at which stations were warming and which were cooling. Figure 2 shows that result.

Figure 2. USHCN minimum temperature trends by station. White is cooling, red is warming.

Interesting. Clearly, “global” warming isn’t. The minimum temperature at 30% of the USHCN stations is getting colder, not warmer. However, overall, the median trend is still warming. Here’s a histogram of the minimum temperature trends.

Figure 3. Histogram of 1,218 USHCN minimum temperature trends. See Menne et al. for estimates of what the various adjustments would do to this raw data.

Overall, the daily minimum temperatures have been warming. However, they’re only warming at a median rate of 1.1°C per century … hardly noticeable. And I have to say that I’m not terrified of warmer nights, particularly since most of the warmer nights are occurring in the winter. In my youth, I spent a couple of winter nights sleeping on a piece of cardboard on the street in New York, with newspapers wrapped around my legs under my pants for warmth.

I can assure you that I would have welcomed a warmer nighttime temperature …

The truth that climate alarmists don’t want you to notice is that extreme cold kills far more people than extreme warmth. A study in the British Medical Journal The Lancet showed that from 2000 to 2019, extreme cold killed about four and a half million people per year, and extreme warmth only killed a half million.

Figure 4. Excess deaths from extreme heat and cold, 2000-2019

So I’m not worried about an increase in minimum temperatures—that can only reduce mortality for plants, animals, and humanoids alike.

But what about maximum temperatures? Here are the trends of the USHCN stations as in Figure 2, but for maximum temperatures.

Figure 5. USHCN maximum temperature trends by station. White is cooling, red is warming.

I see a lot more white. Recall from Figure 2 that 30% of minimum temperature stations are cooling. But with maximum temperatures, about half of them are cooling (49.2%).

And here is the histogram of maximum temperatures. Basically, half warming, half cooling.

Figure 6. Histogram of 1,218 USHCN maximum temperature trends.

For maximum temperatures, the overall median trend is a trivial 0.07°C per century … color me unimpressed.

Call me crazy, but I say this is not any kind of an “existential threat”, “problem of the century”, or “climate emergency” as is often claimed by climate alarmists. Instead, it is a mild warming of the nights and no warming of the days. In fact, there’s no “climate emergency” at all.

And if you are suffering from what the American Psychiatric Association describes as “the mental health consequences of events linked to a changing global climate including mild stress and distress, high-risk coping behavior such as increased alcohol use and, occasionally, mental disorders such as depression, anxiety and post-traumatic stress” … well, I’d suggest you find a new excuse for your alcoholism, anxiety, or depression. That dog won’t hunt.

My very best to everyone from a very rainy California. When we had drought over the last couple of years, people blamed evil “climate change” … and now that we’re getting lots of rain, guess what people are blaming?

Yep, you guessed it.


As Always: I ask that when you comment you quote the exact words you’re discussing. This avoids endless misunderstandings.

Adjustments: This raw data I’ve used above is often subjected to several different adjustments, as discussed here. One of the largest adjustments is for the time of observation, usually referred to as TOBS. The effect of the TOBS adjustment is to increase the overall trend in maximum temperatures by about 0.15°C per century (±0.02) and in minimum temperatures by about 0.22°C per century (±0.02). So if you wish, you can add those values to the trends shown above. Me, I’m not too fussed about an adjustment of a tenth or two of a degree per century, I’m not even sure if the network can measure to that level of precision. And it certainly is not perceptible to humans.

There are also adjustments for “homogeneity”, for station moves, instrument changes, and changes in conditions surrounding the instrument site.

Are these adjustments all valid? Unknown. For example, the adjustments for “homgeneity” assume that one station’s record should be similar to a nearby station … but a look at the maps above show that’s not the case. I know that where I live, it very rarely freezes. But less than a quarter mile (1/8 km) away, on the opposite side of the hill, it freezes a half-dozen times a year or so … homogeneous? I don’t think so.

The underlying problem is that in almost all cases there is no overlap in the pre- and post-change records. This makes it very difficult to determine the effects of the changes directly, and so indirect methods have to be used. There’s a description of the method for the TOBS adjustment here.

This also makes it very hard to estimate the effect of the adjustments. For example:

To calculate the effect of the TOB adjustments on the HCN version 2 temperature trends, the monthly TOB adjusted temperatures at each HCN station were converted to an anomaly relative to the 1961–90 station mean. Anomalies were then interpolated to the nodes of a 0.25° × 0.25° latitude–longitude grid using the method described by Willmott et al. (1985). Finally, gridpoint values were area weighted into a mean anomaly for the CONUS for each month and year. The process was then repeated for the unadjusted temperature data, and a difference series was formed between the TOB adjusted and unadjusted data.

To avoid all of that uncertainty, I’ve used the raw unadjusted data. 

Addendum Regarding The Title: There’s an Aesop’s Fable, #35:

“A Man had lost his way in a wood one bitter winter’s night. As he was roaming about, a Satyr came up to him, and finding that he had lost his way, promised to give him a lodging for the night, and guide him out of the forest in the morning. As he went along to the Satyr’s cell, the Man raised both his hands to his mouth and kept on blowing at them. ‘What do you do that for?’ said the Satyr. ‘My hands are numb with the cold,’ said the Man, ‘and my breath warms them.’ After this they arrived at the Satyr’s home, and soon the Satyr put a smoking dish of porridge before him. But when the Man raised his spoon to his mouth he began blowing upon it. ‘And what do you do that for?’ said the Satyr. ‘The porridge is too hot, and my breath will cool it.’ ‘Out you go,’ said the Satyr, ‘I will have nought to do with a man who can blow hot and cold with the same breath.’”

The actual moral of the story is not the usual one that people draw from the fable, that the Man is fickle and the Satyr can’t trust him.

The Man is not fickle. His breath is always the same temperature … but what’s changing are the temperatures of his surroundings, just as they have been changing since time immemorial.

We call it “weather”.

via Watts Up With That?

March 11, 2023 at 12:20PM

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