Global warming and urban heat pose severe risks to residents of often outdated, non-HVAC social housing in Australia, particularly vulnerable low-income households experiencing energy poverty. These risks are expected to intensify under future climate conditions, underscoring the urgent need for strategies to improve thermal comfort. This study evaluates passive thermal retrofits for high-rise social housing in Sydney under a projected climate scenario in 2050 (RCP4.5). The retrofits include combinations of heat adaptation (i.e. external shading, reflective coatings, and double glazing), as well as adaptation measures to cold (i.e. external mineral wool insulation). The analysis focuses on reducing extreme discomfort hours, defined as indoor temperatures exceeding 30 °C or falling below 16 °C. Under the projected RCP4.5 2050 climate conditions, double glazing combined with mineral wool results in the most effective retrofit for colder periods, reducing cold hours by 23% on average. However, during hotter periods, overhang shading combined with mineral wool proves to be the best option, reducing hot hours by 50%. This scenario also provides optimal year-round thermal comfort, with a 30% reduction in overall discomfort hours. The findings offer valuable insights for policymakers and housing authorities to develop effective climate-responsive retrofits.