AbstractThe late 1930s and early 1940s saw strong climatic anomalies in the tropical Pacific basin. In this paper we combine an ocean‐modelling aproach to the investigation of the Pacific climate of this period with a multi‐parameter data analysis. It is shown that a large and deep pool of warm water in the western Pacific in the late 1930s acted as an energy source for the strong and prolonged El Niño event of the early 1940s and its rapidly following successor. Remote off‐equatorial Rossby‐wave forcing plays a prominent role in the generation of thes