We quantify seasonal prediction skill of tropical winter rainfall in 14 climate forecast systems. High levels of seasonal prediction skill exist for year‐to‐year rainfall variability in all tropical ocean basins. The tropical East Pacific is the most skilful region, with very high correlation scores, and the tropical West Pacific is also highly skilful. Predictions of tropical Atlantic and Indian Ocean rainfall show lower but...

This study investigates the feasibility and presents an assessment of probabilistic rainy season onset forecasts for São Paulo, Brazil, located in a region with a well‐defined wet season from mid‐austral spring (October) to austral autumn (March/April). The probabilistic forecasts were produced with (1) a simple empirical Cox‐regression model using July Niño‐3 index as predictor, (2) the dynamical coupled atmosphere‐land‐surfa...