The variability of sea surface temperature fronts in the western North Pacific is investigated by using satellite and shipboard data. On a 100 km by 100 km grid and on a time step of 1 week the satellite recognizes the subarctic front, the subtropical fronts, and one to two fronts associated with the Kuroshio intrusion. The subarctic front is centered near 42¿N and can be seen throughout the year. Frontal gradients vary from 5¿C/100 km in winter to 2¿C/100 km in summer, and deviations from the mean latitude are small. Th subtropical front is seen only from late fall to early summer in the latitude range between 28¿N and 33¿N. Maximum frontal gradients are of the order of 3¿C/100 km and occur in late spring. Kuroshio fronts occur sporadically in the latitude range between 35¿N and 37¿N. Because of the meandering nature of this current and of the rather coarse resolution used, these fronts are not consistently seen. The findings by satellite are in broad agreement with thoe derived from shipboard observations employing a similar sampling scheme. To study the relationship between satellite-derived temperature fronts and atmospheric flow patterns, the subtropical front was related to the configuration of the wind stress field. It was found that the oceanic front occurred near a persistent atmospheric front in a region where the vorticity and deformation of the wind stress change sign.