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CET 30-Year Averages

September 7, 2021

By Paul Homewood


The World Meteorological Organisation is clear about defining climate average:


It is disappointing then that the Met Office still continues to use the 1981-2010 period as its base. By doing this, of course, it exaggerates temperature increases in the UK.

If we look at the Central England Temperature mean temperatures, for example, we see that both winter and spring this year were colder than average, whilst summer was only 0.3C warmer:



The calendar year to date is actually 0.5C colder than average.

What the climate used to be forty years ago, I would suggest, is utterly irrelevant to most people, who are used to living in the current climate.

  1. Harry Passfield permalink
    September 7, 2021 7:19 pm

    You can bet that if the projections from the newly-defined 30-year periods started to show a decline they would redefine them.

    BTW, OT: Did anyone get the breathless news on BBC yesterday that dragonflies in the UK are moving because – you guessed: CC! Like they are sensitive to a fraction of a degree over a long period of time and cannot adapt.

    • Phoenix44 permalink
      September 8, 2021 7:58 am

      A story that is almost certainly untrue. Dragonflies have extremely short life spans. What is happening to some long term average is completely irrelevant them. Have any recent years be warmer than any year ever? No. So Dragonflies don’t notice anything.

      • dave permalink
        September 8, 2021 9:46 am

        My son said to me that he saw a lot of dragon flies in Sussex a few days ago.
        They are gone now. As Phoenix44 says, they only live for two weeks. Long enough for sex. The smooth ‘I am with you for life, baby!’ works for the male of the species, I suppose.

        We truly live in an age of wall-to-wall morons. When firing up my AOL Mail there comes up an (unwanted) news ‘service.’ I noticed a news item today about Covid deaths in the UK among vaccinated and unvaccinated people and unwisely peeked at it. Incredible to relate, the ‘jounalist’ writes that between February and August of this year there have been 1,047 deaths among the double-dosed and 536 [sic] deaths among the unvaccinated; and then, using her brilliant scientific and mathematical skills, explains that the greater number of deaths among the vaccinated is due to there being more of them. Can she not see that she has dropped two noughts off 53,600? Is she in fact even conscious?

        As for the Met Office, I see that if they were following the rules of their ruling professional body they would be using 1991-2020 as the reference period, by now. Scientists are not allowed to pick and choose which rules they follow!
        Unless, that is, they clearly announce themselves as ‘Dissenters.”

        I noticed that Roy Spencer, of satellite measurements fame, changed his base period at the beginning of the year, which I found a little irritating,
        I see now that he was simply doing the right thing.

  2. Broadlands permalink
    September 7, 2021 7:20 pm

    “It is disappointing then that the Met Office still continues to use the 1981-2010 period as its base.”

    That pales by comparison to what NASA-GISS has done. Hansen et al. kept their 1950-1980 base period but changed the reference temperature from 59°F down to 57°F. Talk about making the warmer past disappear in an instant. The 40s “blip” is gone. No more global warming? 1990 and 1995 no longer record warm years???

    It’s one thing to change base periods, but it is unheard of the KEEP the base period and change the temperatures. They claim they did it for consistency with NOAA’s 20th century base period. How nice.

  3. MrGrimNasty permalink
    September 7, 2021 7:38 pm

    Hard to get alarmed either way.

    R5Live this morning, Mr self-proclaimed impartiality hilariously not self-aware Nicky Campbell announced the supposed spread of dragonflies due to warming as a small crumb of comfort in a sea of climate devastation (words to that effect).

    Of course it is more complicated than the warming message pushed as the main driver.
    Suitable habitat has been created. And this is all based on notoriously inconsistent ‘citizen science’ and patchy records anyway.

    Click to access State-of-Dragonflies-2021-final-moderate.pdf

    As ever the truth is sidelined and climate change pushed to the fore.

    “The increase in many species, if not all, we can put down to a combination of climate warming and more or better wetland habitats such as an increase in the number of ponds, lakes, gravel-pits and reservoirs in recent decades,”

  4. C Lynch permalink
    September 7, 2021 7:49 pm

    Met a New Zealand friend of mine on a cycle this evening. I commented on the harsh winter they just had. He told me that they had frequent snowfall even to low levels – even on the North Island and frost was widespread. But he said that “experts” were claiming that when you added all the day and night temperatures together and “homogenised” them it was actually the warmest winter on record!!
    To be fair to him he was able to see this for the obvious sophistry that it is.
    It’s a good example, though, of how brazen this fraud has become.

  5. Jack Broughton permalink
    September 7, 2021 8:35 pm

    The “i” has several gullible reporters who trumpet any climate-change fear stories that are sent to them. The extra-gullible Madeleine Cuff is waxing poetical about the “success of the Birmingham Clean Air Zone”. She also claims that Rupert Murdoch has instructed his editors to reject “attacks on climate science”.

  6. September 7, 2021 9:11 pm

    They’ll probably quietly do it after COPOUT 26 has finished

  7. Broadlands permalink
    September 7, 2021 9:20 pm

    This dragonfly stuff is nonsense. Designed to get headlines and more funding? And even if it isn’t, and CO2 is the proximate cause, there is nothing that can be done to stop it anyhow. Animals in the past (in the warm1920s, 30s) made migrations very similar as they are doing now.

    Drinkwater, 2006 wrote: “Ecosystem changes associated with the warm period included a general northward movement of fish. Boreal species of fish such as cod, haddock and herring expanded farther north while colder-water species such as capelin and polar cod retreated northward. The warming in the 1920s and 1930s is considered to constitute the most significant regime shift experienced in the North Atlantic in the 20th century.”

  8. dearieme permalink
    September 7, 2021 9:25 pm

    “What the climate used to be forty years ago, I would suggest, is utterly irrelevant to most people”. Most people have little memory of the weather in the last decade, never mind forty years ago. It’s their knowledge of that that encourages the lies of the Met Office, the Beeb, the Guardian, and the like.

    The exception is if something is marked by a qualitative difference. My parents pointed out to me that they had skated on the local river whereas it never froze in my childhood (or since, I’ll bet).

    • Micky R permalink
      September 12, 2021 11:49 am

      Forty years ago, the weather in the UK was changeable, In 2021, the weather in the UK remains changeable. I don’t see fractional changes in average annual temperature as being climate change.

  9. September 7, 2021 9:27 pm

    Reblogged this on Jaffer's blog.

  10. Colin permalink
    September 7, 2021 11:26 pm

    Meanwhile in Scotland the Climate Emergency has resulted in an inconsequential increase of around 0.5 °C since 1990, those who think this is serious might consider that most thermometers have gradations of 1 degree and therefore don’t show this catastrophic heating, and in fact a flesh and blood human being can only detect it a subliminal way. When you consider day to day and even yearly variation in temperature it’s laughable that we consider this warming as a serious problem.

  11. tomo permalink
    September 8, 2021 2:01 am


    some epic COP26 (expensive) bilge in my local rag – probably hitting hundreds of local papers tomorrow…. courtesy of the climate clowns at The Press Association.

    see here

    • Coeur de Lion permalink
      September 8, 2021 6:09 pm

      All delegates must have health certificates as required for assembling in France and wear face masks throughout. Non vaccinated delegates must be vaccinated and held. All Glaswegians to be required to stay well clear and report any symptoms. Full news cover of these rules now.

  12. John Hultquist permalink
    September 8, 2021 3:42 am

    An average temperature, regardless of years, is not climate.
    Also, there is not a climate emergency. And, CO2 is not
    the answer to a non-problem.

  13. Phoenix44 permalink
    September 8, 2021 8:15 am

    Why 30 years? If climate has not changed before we changed it, why not use the longest period we have for comparison? 30 years is a wholly arbitrary period. And if the various cycles that may dominate much weather exist, you need to be comparing like for like – it’s absurd to compare a positive and negative AMO for example, in terms of “change”.

    In any event, the mean is meaningless. As we have seen here in the last few weeks, what we are actually experiencing is a change in distribution at various levels – more years with hot days but NOT more hot days in any given year. That increases the mean over those years but an average increasing in that way is not “hotter” in the way portrayed by Alarmists and in the media. Nor is it a warming trend. This is an excessively reductionist approach, almost certainly used to disguise that the forecasts are not coming true.

    • dave permalink
      September 8, 2021 11:11 am

      “…mean is meaningless…”

      Definitely pointless.

      The main idea of the mean, when imported from elementary arithmetic into descriptive statistics in the 19th century, was that is should be a representative. If you are told that the average height of a man in England is 1.80 meters you can choose a man who is that tall and then say, “if I recruit a hundred men at random most of them will be like him in height.”

      Now, if the next generation of men has an average height of 1.85 meters a man of 1.80 meters is STILL a good representative; just not quite AS good. The change of 0.05 meters is genuine, but leaves 1.80 meters still in ‘the sweet spot’ of acceptable representatives.

      So, if the ‘mean of the max daytime temperatures in July* in Margate’ was 21.3 C last year and is 21.6 this year, has the ‘representative’ temperature had a significant change? “Oh it was much hotter this year! I did not feel it but the average says so!”

      If you average the July averages for thirty years, does a change in this signify?**

      *Climatologists of the past thought that taking monthly means was sensible because the ‘seasons’ last for three or so months. Taking a yearly mean was not even considered.
      No living creature ‘averages’ his experience of winter and summer!

      **A reason for the ‘thirty years mean’ was that scientists always suspected that cycles shorter than this existed, and that it was possible to get a ‘run’ of dry summers, or cold springs, or whatever; and one should therefore be patient and wait them out. As a practical matter, you can not change an economy radically for transient conditions.

  14. Terence Carlin permalink
    September 8, 2021 8:45 am

    Having given up with trying to get an answer as to how the GISS average temperatures were produced prior to the 1950’s my next port of call was The mean temperature of central England, 1698-1952 produced by Gordon Manley his findings were published in the Royal Meteorological Societies Journal Vol 79, pp 242-261,this paper is still cited as the basis for CET averages 1698 1952 ( the paper sits behind a pay wall $42 on the RMS website) I have a copy in Pdf format that the RMS sent me when I pointed out that they have a commitment to public engagement.
    Manley’s paper was produced by diligent research and his purpose in producing the paper was to try and identify patterns or cycles of weather that would affect crop production and for this purpose it was an excellent paper. However, it is worth reading as it illustrates and highlights and accepts the high level of uncertainty in much of the results which brings me back to the confidence levels that the Met assign to this period of the temperature record.

  15. Eddie P permalink
    September 9, 2021 6:26 am

    Just for fun I calculated a decade’s mean temperature for past centuries using the CET seasonal records.
    The 1720’s had a mean of 9.3C; the 1820’s was 9.4C; the 1920’s was 9.4C (despite all that nasty temperature raising CO2 put out by the industrial revolution); and the 20teens was 10.1C.

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