Macquarie Island, a remote UNESCO World Heritage site in the Southern Ocean, is becoming wetter, with rising rainfall waterlogging its slopes and pushing back iconic megaherbs such as Pleurophyllum and Stilbocarpa. New research using 45 years of high-quality Bureau of Meteorology and Australian Antarctic Division data shows annual rainfall has increased by 28% since 1979, a change that common reanalysis products like ERA5 significantly underestimate. The study finds that the increase is not due to more frequent storms, but to storms producing more rain when they occur, linked to shifts in Southern Ocean storm regimes. If similar intensification is happening across the wider storm belt, it could mean roughly 2,300 gigatonnes of extra freshwater entering the high-latitude Southern Ocean each year, strengthening ocean stratification, altering currents, and affecting carbon and nutrient cycling. The analysis also suggests the Southern Ocean is cooling itself 10–15% more through evaporation, effectively “sweating” in response to climate change, with implications for the global climate system that are only beginning to be understood.