Overall Bourke raw data show a cooling maximum temperature trend from 1880 of 1.7ºC per century. After adjustment ACORN at Bourke shows a slight warming temperature trend. This change of maximum temperature trend has a great effect on the whole of Australia’s temperature record. The BOM has offered no particular reason for these adjustments.
“negative adjustments are somewhat more numerous for minimum temperatures, which is likely to result in ACORN-SAT minimum temperatures showing a stronger warming trend than the raw data do"