<p>The warming of ocean temperature under climate change is a significant concern for maintaining a healthy ocean environment. In recent years, many regions of the world’s oceans have experienced unusually high temperatures, leading to frequent occurrences of marine heatwaves. Here, comparisons between two sets of 3-member ensemble eddying ocean simulations forced by two different atmospheric wind products suggest high sensitivity of the sea surface temperature in the Kuroshio-Oyashio confluence and Oyashio southward intrusion regions in the northwestern Pacific to the atmospheric wind in the mid-latitude North Pacific. Differences in the northward mass transport off the east coast of northern Japan, the meridional position of the Kuroshio Extension, and eddy activity play a role in the sea surface temperature differences. The ocean responds to the atmospheric wind in the mid-latitude North Pacific through barotropic and partially through baroclinic Rossby waves. In 2018–2022, the sea surface temperature in the region was high. In each ensemble simulation, the high temperature appears to be caused by the oceanic responses to the atmospheric wind variations, although the temperature was too high in the period compared to the observation. Our model suggests the possibility that the marine heatwave events in this region were partially attributed to the high sea surface temperature persisting in the period. Therefore, the sea surface temperature variations in the northwestern Pacific through the oceanic response to the atmospheric wind may be crucial for fisheries in the region with rich marine ecosystems.</p>