Thermal tolerance (ED50) data used to compare previously published regional (Florida Reef Tract, Coral Sea, Red Sea) coral thermal tolerance with Heron Island, Great Barrier Reef values measured in 2022

Variable temperature regimes that expose corals to sub-lethal heat stress have been recognized as a mechanism to increase coral thermal tolerance and lessen coral bleaching. However, there is a need to better understand which thermal regimes maximize coral stress hardening. Here, standardized thermal stress assays were used to determine the relative thermal tolerance of three divergent genera of corals (Acropora, Pocillopora, Porites) originating from six reef sites representing an increasing gradient of annual mean diel temperature fluctuations of 1–3°C day-1. Bleaching severity and dark-acclimated photochemical yield (i.e., Fv/Fm) were quantified following exposure to five temperature treatments ranging from 23.0 to 36.3°C (see Related Datasets). This data set contains the comparison of thermal tolerance across studies.