Located between the tropics and the equator, the tropical rain belt plays an important role in water and energy cycles worldwide. In this video, HANS SEGURA explores the extent to which a new generation of simulations can help us to understand the tropical rain belt. Comparing simulation data with observations, Segura’s work shows that the models can accurately predict the location and area of the tropical rain belt over land. The simulations are shown to be less reliable with regard to many of the world’s oceans. Suggesting hypotheses as to why this might be the case and outlining ways in which further work could lead to improvements, Segura’s work has broad relevance not only to those interested in climate change but in how the climate works.