In September 2019, the largest die-off in the history of Newfoundland’s finfish aquaculture industry occurred in Fortune Bay, a large embayment located on the south coast of the island. This die-off was quickly attributed to unusually high water temperatures that would have occurred over a ‘prolonged period’ and would, consequently, have reduced dissolved oxygen availability to the farmed fish. Using the results of recent oceanographic investigations, we will show how the physical environment of Fortune Bay varies from timescales of hours to decades and what we see as the most important dynamics which can affect farmed fish well-being and aquaculture activities more generally. We will investigate whether the summer of 2019 can be qualified as an ‘outlier’ or ‘the new norm’ or whether it was within the ‘normal variability’ of the system. We will conclude to offer avenues of other factors that may have played a role in this massive die-off.