Yeah, these records are totally meaningless in every sense of the word.
Modern data(ie. their ability to 'average') is far more prevalent now, then say in the early 1900s, or late 1800's.
eg. pre 1940, there was no data for Oodnadatta, as the records only started in this year for that location.
And they close many old sites and relocate them to alternative grounds(eg. that I know of Melb regional office close in 2015, and now Melb is measured at a new site since 2013)
So they make claims that Melb will cop a 'new record' high temp for December this coming Friday(expected 43), which is technically correct if you just look at the data that's easily available.
But this claim is only true if you only take into consideration that the data is only available from 2013, unless you specifically find the hard to locate tick box that reveals the closed station too.
The closed station data shows that Melbourne has had many >42°C days in December since the 1850's.
That I've counted, 3 previous instances of 43°C or higher in Dec in Melb, all pre 1900's.
5 instances of 42.9°C or more in Melb in Dec, only 1 of which was in this modern, climate change era.
Records come and go, and are open to 'interpretation' as one sees fit to create them based on the specific data they want to use.
But as a record breaking event, this supposed average temp across Aus as a whole is useless data. The level of precision of collating that data is higher now than previously.

