In this vulnerable climate hotspot, accurate Sahelian summer rainfall (SSR) forecasting is essential for preventing hydrometeorological disasters. In order to demonstrate that the sea surface temperature interhemispheric dipole in winter (SSTIDw) has a significant impact on SSR, the current study uses observational data from 1950–2023. Throughout the spring and summer, a positive SSTIDw anomaly—characterized by comparatively warmer Northern Hemisphere SSTs—leads to cyclonic circulation and persistently negative surface pressure anomalies. In addition to strengthening anomalous westerly and southwesterly flows across the Atlantic and the Guinea Coast, this strengthens the Saharan Heat Low (SHL) and increases moisture flux convergence and rainfall in the Sahel. The researchers create a linear regression model based on SSTIDw that adeptly captures SSR features. The results demonstrate how SSR’s multi-month lead time predictability is essential for Sahelian decision-making that takes climate change into account.