Wind-driven upwelling along southwest Greenland, accompanied by offshore freshwater transport, has potentially strong implications for Labrador Sea deep convection and the Atlantic Meridional Overturning Circulation. Here we use a decade of mooring measurements from the Overturning in the Subpolar North Atlantic Program (OSNAP), along with atmospheric reanalysis fields, to investigate the seasonality and year-to-year variation in the upwelling. Over the time period 2014–2024 the number of summer events increased, while the mean duration of winter events decreased for the first seven years and then rebounded. The latter is consistent with the winter North Atlantic Oscillation (NAO), whereas the relationship between the number of summer events and the summer NAO is counterintuitive. A large number of the summer events occurred under an atmospheric scenario that is not typically associated with upwelling in this region. A storm track analysis reveals that these conditions are typical of a low NAO state, thus explaining the above-noted counterintuitive relationship. Our results highlight a previously underappreciated role of high-pressure systems in driving upwelling variability and provide new insights into the factors controlling upwelling along southwest Greenland.

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