Surface heating occurs over the streamline of the Antarctic Circumpolar Current (ACC) and balances the heat transport associated with the global meridional overturning circulation. With a combination of ocean assimilation model output, objectively analyzed products, and atmospheric reanalysis, this paper investigates the mechanism of climatological surface cooling in the Pacific sector with zonal asymmetry. The poleward shift of the ACC path in the Pacific with barotropic potential vorticity conservation was found to account for this cooling. The southward transport of warm/wet surface waters encounters relatively cold/dry air at high latitudes, causing strong turbulent heat fluxes. Sensible heat flux related to the sea‐air heat convection plays an equivalent role alongside the sea surface evaporative latent heat flux, both of which dominate the surface cooling in the Pacific sector. Solar radiation decreases with a poleward meandering of the ACC, which aggravates the cooling process. A significant seasonal cycle of the ensemble mean net surface heat flux (Qnet) is demonstrated, that is, approximately half‐year heating (cooling) during austral warm (cool) seasons. The estimated magnitude of Qnet over the ACC is approximately 20 W m−2 by averaging 10 heat flux climatologies and 4 W m−2 in an ocean state estimate model. However, efforts are still needed to reduce the excess heat flux over the sea surface in the Southern Ocean for the heat flux products. Plain Language Summary The Antarctic Circumpolar Current experiences surface heating that balances the global meridional heat transport associated with meridional overturning circulation, in which the waters in the North Atlantic subduct due to surface cooling and upwell to the surface in the Southern Ocean. In this paper, the author shows the zonal asymmetry of the climatological surface heat flux over the Antarctic Circumpolar Current. In the Pacific sector, the current meanders poleward as a result of topographic constraints. The solar radiation decreases with increasing latitude. The poleward shift brings warm waters to the higher latitudes, and the ocean releases extra heat under a colder atmosphere. Thus, the Antarctic Circumpolar Current is cooled in the Pacific sector, which is different from the other sectors around the circumpolar belt. How much heat flux enters the Antarctic Circumpolar Current? This paper also gives an ensemble mean estimate of the heat values based on a combination of ocean assimilation model output, objectively analyzed products, and atmospheric reanalysis. The magnitude of the net surface heat flux is approximately 20 W m−2 according to 10 heat flux climatologies and 4 W m−2 in an ocean state estimate model. Key Points The mechanism of zonal asymmetry in net air‐sea heat flux climatology over the Antarctic Circumpolar Current is investigated Cooling processes occur in the Pacific sector with solar radiation less than the turbulent heat fluxes The poleward shift in the warm/wet ocean encounters cold/dry air, which causes large turbulent heat fluxes and determines surface cooling