The correct minimum temperature for Goulburn on 2 July, 2017 is -10.4 recorded at 6.30am at Goulburn Airport AWS… The Bureau’s quality control system, designed to filter out spurious low or high values was set at -10 minimum for Goulburn which is why the record automatically adjusted.
The software was programmed - and presumably remains programmed - to reject what the equipment says is true, and replace it with what someone else decided to program the software to say is true.
It's not a conspiracy theory to point out the fact - because it is an objective fact - that the BOM's opinion as to what is spurious is merely that: an opinion.
And whilst anyone could say, correctly, that whatever temperature the equipment represents as true may nonetheless be untrue as an objective fact, it is equally correct to say that BOM's opinion as to what is a spurious temperature may nonetheless be untrue as an objective fact.
Who knows why the BOM's "quality control" system was set at - 10 minimum for Goulburn. It might have been because the person instructing the programmer liked round numbers. It might have been because the Giant Spaghetti Monster (blessed be the Giant Spaghetti Monster) used a noodly appendage to change the code in the software. It might have been because the person who chose the threshold had dedicated his or her life to climatology and weather statistics and forecasting, and earnestly believed, based on his or experience, that the temperature could never go below - 10 at Goulburn.
It doesn't matter a fcuk what the motivation was: The decision to set - 10 as the 'spurious threshold' was, objectively, a mistake, unless someone can prove that the temperature measured by the AWOS was wrong and the temperature at that site will never fall below - 10.
Which brings me back to the delicious paradox of all this: Nobody can actually prove what the actual temperature was.
If all that happens out of these events is that BOM defends its software and the validity of its "quality control" system, I'm hardly surprised conspiracy theorists draw the inferences they draw.