We examine the seasonal evolution of analyzed wind stress curl (WSC) over the northeast Pacific Ocean. The strongest WSC features are associated with wind maxima on the flanks of the North Pacific High and Aleutian Low, especially in coastal regions. A strong, seasonally-migrating WSC dipole (positive inshore, negative offshore) is evident year-round over the California Current System (CCS). We compare the WSC fields to observed upper ocean temperatures to test the hypothesis that seasonal variations in overlying WSC strongly impact temperatures just below the seasonal thermocline. The hypothesis is supported along most of the west coast, where the WSC seasonal cycle is strong and subsurface temperature data are relatively abundant. In open ocean regions, there is little clear evidence for or against the hypothesis due to weak WSC signals and a lack of subsurface data.