Context. Mammals inhabiting arid and semi-arid regions are often exposed to extreme conditions and may rely on refuges for survival. The greater stick-nest rat (Leporillus conditor) is a threatened, nest-building rodent that once occupied large parts of semi-arid Australia. The species became restricted to two offshore islands, but has now been translocated several times, with translocation failures attributed to predation, unsuitable habitat and drought. Aims. We studied a translocated population of greater stick-nest rats at Australian Wildlife Conservancy's predator-proof fenced area at Mt Gibson Wildlife Sanctuary in Western Australia. We documented the population trajectory over time, characterised and modelled the thermal properties of above-ground stick-refuges and recorded data on habitat use. Methods. We used live trapping data to estimate population abundance over time. We documented the structure and thermal and humidity profiles of stick-refuges and conducted vegetation surveys comparing areas inhabited by greater stick-nest rats to adjacent uninhabited areas. Results. We found that: (i) greater stick-nest rat abundance declined to a barely detectable level during a severe hot drought; (ii) internal refuge temperatures were typically cooler than external temperatures, but the buffering effect was ineffective on extremely hot days; and (iii) stick-nest rats inhabited sites with a relatively high abundance of salt-tolerant shrubs, which are highly susceptible to drought and of which there is limited availability within the fenced area. Conclusions. Extreme heat wave conditions and drought were related to a sharp population decline. Stick-refuges occupied by greater stick-nest rats at our study site provided limited thermal buffering, and the drought likely reduced the availability of food resources. As the extent of salt-tolerant shrubland is limited within the fenced area at Mt Gibson, a lack of suitable habitat may have contributed to the observed population decline during the hot, dry period. Implications. Our findings suggest that regions with more moderate climates and larger areas of suitable vegetation may be better suited as translocation sites for this species in the future. More broadly, our study highlights the need for further research on how Australia's rodents will respond to elevated temperatures and increased drought as climate change progresses.