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Australia’s new hottest day just “discovered”, not Albany or Oodnadatta, but Carnarvon (51 degrees in 1953!)

Australia's hottest day ever. Map.

Who knew? With intrepid dedication the Australian BoM has uncovered our hottest ever day, buried under erroneous calculations, hidden from view in High Quality expert data sets that were World Class til they weren’t. Strangely the BOM hasn’t issued a press release, even though their supercomputer-marketing team put out a Hottest Ever January media release within hours of January ending. It appears the BOM hasn’t even issued a press release to tell the world they’ve finished the third complete reanalysis of Australian temperature history.

Luckily for the BOM, which may have run out of bytes or letters of the alphabet, volunteers like Chris Gillham of the unofficial BoM audit team noticed that the BoM ACORN dataset has become ACORN2. So we’d like to tell the world. Once again, the genius at the BOM is able to retrospectively compensate for all the flawed sites and thermometers that kept reading too high. Incredibly, no one noticed for a hundred years.

As we launch ACORN2 let’s remember how proud the BOM were of ACORN1. This is from them back in 2017:

Bureau of Meteorology statement on temperature observations


The Bureau of Meteorology holds the integrity of our weather observations and climate data to the highest possible standards. The Bureau rejects allegations aired in some media outlets that it has sought to tamper with temperature data.

So the highest possible standards just got higher. Luckily they have arrived in time to find extra warming trends before the next Australian election.
Warming trends with adjustments again?
From Chris Gillham:  ACORN 2 influence on Australian temperature trends

An example of the haywire homogenisation that’s rewritten Australia’s temperature history is that Carnarvon can now claim to have had Australia’s hottest ever day, with ACORN 2 listing the town at 51.0C on 23 January, 1953. The bureau names Oodnadatta Airport at 50.7C on 2 January 1960 as Australia’s hottest ever day.

In the ACORN 1 dataset, 23 January 1953 at Carnarvon was 48.5C, and in RAW it was 47.7C. ACORN 1 lists Albany at 51.2C on 8 February 1933 but ACORN 2 cools this day to 49.5C (RAW 44.8C).

So the original Carnarvon record just got 3.3C hotter. The Albany record which got 7 degrees warmer in the last round has dropped back 2.7C. Lordy, look at the size of those centigrade wrestling matches!

The original ACORN may have been a bit rushed as it arrived just in the nick of time to save the BOM HQ dataset from being audited by the Australian National Audit Office. (Something Cory Bernardi requested with our help). The old HQ stood for High Quality. So much for that.

Cooling the past once again?

Thermometers in 1910 -1940 were reading far too high despite them being in Stevenson Screens at some of our best sites:


Australian Bureau of Meteorology, Australian temperatures, adjustments to raw readings, ACORN and ACORN2.


What bad luck. All this time the raw data was conspiring to hide Australia’s true cooler history.

It was even more true of Minima:

Australian Bureau of Meteorology, Australian temperatures, adjustments to raw readings, ACORN and ACORN2.


It’s a big news day when a town is even forecast to maybe possibly beat the old Oodnadatta record, so I expect (not) that the media will go crazy about this new discovery, or they would if the hottest ever day was not 60 years ago.

There’s a lot more we will say about ACORN2. Questions we are all waiting to find out — does it still have nearly a thousand days where the minima are higher than the maxima? Are they still creating monthly square wave patterns in the data as temperatures whip-saw up and down with adjustments going a degree either way on each side of New Years Eve? Just how much has this cooled the past and warmed the trend and where are these changes most apparent? Will the BOM call these adjustments “neutral” like the last time. How do they compensate for the Urban Heat Island effect, for the introduction of electronic super sensitive thermometers and all the site moves?

The Australian people pay a million dollars a day for this inept and biased operation.So far the only thing new about this version is that the BoM don’t seem so keen to tell the world about yet another revision of history.

For the record, when this new version was “launched” a year ago, I went through the full history of scandals and revisions in one post (just in case you want to be reminded how many times the BoM has shifted the goal posts).

Thanks to all the dedicated BOM Audit team who don’t get paid, thanks to Jen Marohasy, Senator Cory Bernardi, Graham Lloyd and The Australian. All of whom have played an important role in keeping the pressure on.


THE BOM LIST grows — Scandal after scandal


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