A permanent large-scale longitudinal maximum of sea surface temperature at mid-latitudes in the eastern North Pacific is explained by a permanent circulation. One part of the circulation consists of a northeastward current near the surface, which extends diagonally from low latitudes on the western side to mid-latitudes on the eastern side of the basin, and a southwestward return flow on either side and underneath the northeastward current. The other part of the circulation consists of mid-latitude eastward and low latitude westward surface currents. The complete circulation is driven by the wind and by the sun, and it conserves mass and transports heat and eastward angular momentum poleward, as required of the ocean. The seasonal east-west movement of the longitudinal temperature maximum is explained by the north-south movement of the diagonal circulation, which follows the seasonal movements of the sun and wind systems. Seasonal variations in the complete circulation are consistent with the balances of mass, heat, and eastward angular momentum being satisfied throughout the seasonal cycle.