Maximum temperatures in Australia are on average not increasing at all. Instead an increase in minimum temperatures explains the ~1C warming observed since 1910.
All these results are from ACORN-SAT which have already been adjusted and homogenised. They are the same as those used by GHCN and CRUTEM. What the data really shows is that night time temperatures across Australia have increased, while daytime temperatures have hardly changed.
To check my results simple download the daily minimum and maximum temperatures from all 112 stations that form ACORN-SAT. Then spatially average all annual maxima and minima temperatures.