The frontogenesis of the North Pacific subtropical sea surface temperature front (NPSTF) occurring from October to the following February is examined quantitatively based on the mixed-layer energy budget equation, with a focus on its connection with the atmosphere above. Diagnosis results show that the net heat flux dominates the frontogenesis from October to December, while the meridional temperature advection in the ocean contributes equally as or even more than the net heat flux in January and February. The atmosphere is critical to the frontogenesis of the NPSTF, including the direct effect of the net heat flux and the indirect effect through the Aleutian low. Further analyses demonstrate that the latent heat flux (the shortwave radiation) dominates the net heat flux in October (from November to February). The meridional temperature advection in the ocean is mostly owing to the meridional Ekman convergence, which is related to the Aleutian low. Climatologically, the strengthening and southward migration of the Aleutian low from October to the following February are characterized by the acceleration and southward shift of the westerly wind to the south, respectively, which can drive southward ocean currents. Correspondingly, the southward ocean currents give the colder meridional advection to the north of the NPSTF in January and February, favoring the frontogenesis. In addition, the Aleutian low plays a role in transforming the dominant effect of the net heat flux to the joint effect of the meridional temperature advection and the net heat flux in January. CESM1.0.3 model with a slab ocean model further confirms the important influence of the atmosphere on the frontogenesis and on the meridional temperature advection.