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 Special Report: The Vanishing Record: How the Bureau Quietly Deleted 274,000 Temperatures and Built Its Climate Data on Unpublished Files

The public cannot verify the ACORN-SAT dataset because the raw data it was built on is either missing, withdrawn, or never published.

In 2007, the Bureau sold a CD containing its raw temperature data. A colleague kept that CD. We compared it, day by day, to what the Bureau currently publishes on its Climate Data Online (CDO) portal.

The result is staggering. Since 2007, the Bureau has quietly removed 274,722 temperature values from the public record.

 Discovery 1: The Bureau Quietly Deleted 274,000 Readings

- Most of these were flagged as "suspect" back in 2007, which is fair enough. But nearly 13,000 of them were flagged as "Y" (Quality Checked). The Bureau certified them as good data in 2007. Today, they are gone.

- The Bureau deleted 19 entire weather stations from the public record. Point Lonsdale Lighthouse lost 7,670 days of data.

- Even more disturbing: they applied different, unannounced rules in different places. In Sydney, they deleted days where the maximum and minimum temperatures were too close together. Elsewhere, they deleted days where they were too far apart.

 Discovery 2: 80,000 Unpublished Readings Used to Build the Climate Record

Inside the ACORN-SAT download, there is a separate zip file labeled "raw data and supporting information."

*This file contains the actual daily readings the Bureau used to build its official climate record. And it contains roughly 80,000 temperature readings that do not exist on the public CDO portal.*

- About a third of these values were on the 2007 CD, meaning they were public once, but have since been withdrawn from CDO.

- The other two-thirds—including 36 years of data at Port Macquarie (1921–1956)—were never published at all.

The Bureau is using 80,000 data points to calculate its official climate trends that the public has never seen and cannot verify.

 

The Bottom Line

The Bureau of Meteorology has a duty to maintain a transparent, verifiable historical record of Australia's climate.

Instead, they have quietly withdrawn 274,000 readings from public view, and used 80,000 unpublished readings to build their official dataset.

This is not a clerical error. This is a systemic failure of data integrity.

The Bureau can fix this.
They can release the complete raw data (including the 80,000 unpublished values), explain why 274,000 values were withdrawn, and fix the backdating flaw in their homogenization algorithm.

Until they do, the ACORN-SAT dataset should not be used for policy or climate analysis without a clear disclaimer: This record is incomplete, unverified, and artificially warmed.

Thanks to Patrick Lloyd and his assistant Claude AI for analysis.