The long‐term memory of the ocean makes sea surface temperature anomalies (SSTAs) become a significant predictor for the subsequent atmosphere, and the tropical ocean is primarily regarded as a major source of atmospheric anomalies. While in North Pacific, the local midlatitude SSTAs also have large contributions but have not been adequately considered yet. We discover a strong connection between the Kuroshio‐Oyashio Extension (KOE) SSTAs in spring and the local atmospheric circulation anomalies in following summer at interannual timescale, wherein, the spring KOE SSTAs are generally independent of tropical ocean, and they are primarily induced by the concurrent atmospheric anomalies via surface heat flux and ocean dynamic processes. The spring KOE SSTAs can persist to summer, and then generate nearly reversed whole‐layer atmospheric circulation anomalies in their north side through both diabatic heating and atmospheric transient eddy forcing. Consequently, precipitation anomalies in Pan‐Pacific regions are distinctly modulated from spring to summer. Plain Language Summary Because of the vast heat‐holding capacity and the long‐term memory of ocean, sea surface temperature anomalies (SSTAs) are usually taken as the significant factors to understand and predict climate anomalies. On interannual timescale, attentions have primarily centered on the tropical SSTAs, but recent studies indicated that the SSTAs in mid‐to‐high latitudes, especially in the Kuroshio‐Oyashio Extension (KOE) could have important feedbacks on the atmosphere. In this study, the KOE SSTAs in spring are discovered to have large interannual variability, and they are independent of the tropical SSTAs but closely linked to the subsequent summer atmospheric anomalies. It is found that the spring KOE SSTAs are mainly forced by the atmosphere via the surface heat flux and the ocean dynamic processes. In turn, they can persist to summer, and then play a dominant role in the air‐sea interaction in North Pacific, inducing remarkable geopotential height anomalies in north side. Consequently, in terms of the KOE SSTAs evolving from spring to summer, the Pan‐Pacific precipitation anomalies are distinctly modulated due to the opposite air‐sea interaction processes in the two seasons. These findings advocate for the use of springtime KOE SSTAs as a predictive indicator for following summer atmospheric and precipitation conditions. Key Points The spring Kuroshio‐Oyashio Extension (KOE) sea surface temperature anomalies (SSTAs) are independent of tropical ocean and primarily forced by the concurrent local atmosphere at interannual timescale The spring KOE SSTAs can persist to summer and exert a delayed cross‐season impact on the subsequent summer atmosphere Associated with the spring KOE SSTAs, precipitation anomalies in Pan‐Pacific regions are distinctly modulated from spring to summer