The feminisation of sea turtle populations is caused by rising sand temperatures on nesting beaches and results in reduced production of male hatchlings. However, for many tropical regions around the world, increasing air temperatures are predicted to increase the frequency of heavy rainfall events, which may counter the feminisation of turtle populations that would otherwise occur. As part of the WWF-Australia ‘Turtle Cooling Project’, we aimed to; (1) determine the importance of heavy rainfall events at key hawksbill (Eretmochelys imbricata) and green turtle (Chelonia mydas) nesting beaches for male hatchling production in the Asia-Pacific region; (2) model past and future hatchling sex-ratios using sand and air temperature data proxies; and (3) use aerial surveys to estimate the breeding sex-ratio at a regionally significant green sea turtle mating ground in the southern GBR, Australia. Our results from aerial surveys indicated an influx of both males and females during the time of courtship, this resulted in a relatively balanced sex-ratio. This is a promising outcome, as many sea turtle rookeries globally are known to have a female-biased primary sex-ratio. The project will provide new insights to better inform conservation managers on sex-ratio trends of key populations and their relative risk to feminisation.