A record-based framework for identifying non-stationarity in daily Australian temperature records from 1950-2023

Record-breaking temperature events are important indicators of climate change, yet detailed statistical analyses of daily temperature records remain limited, particularly for Australia. Here, we focus on absolute daily upper records, temperatures that exceed every previous observation for a calendar day, and apply a record-based statistical framework to daily maximum and minimum temperature series from 53 high-quality Australian stations (1950–2023) to assess whether observed records adhere to stationarity. Permutation-based hypothesis testing and change-point detection reveal widespread non-stationarity, with shifts beginning as early as the 1970s. Minimum-temperature upper records show earlier and more pronounced deviations than their maximum counterparts, especially in coastal locations. The spatial analysis highlights coastal–inland contrasts, with coastal minimum-temperature upper records strongly correlated with rising sea-surface temperatures (SST). These findings offer the first comprehensive evidence of non-stationarity in daily upper temperature records across Australia, identifying key geographic and climatic drivers of new record formation. The results underscore the value of record-based approaches for local-scale climate-risk assessments, supporting more accurate adaptation strategies and resilience planning under ongoing warming trends.