The hydrology of Lake Victoria is, to a large extent, a function of the balance between rainfall on and evaporation from the lake surface. Historical climate variability has resulted in significant fluctuations in the water level in the lake. Climate models predict changes to the balance between precipitation and evaporation over the coming decades, with potentially serious impacts on the lakes water balance. These impacts have implications for the approximately 30 million people living around the lake, as well as further downstream in the Nile River basin. Hydropower, fisheries and transport are among the sectors that may be affected by changes to the water balance. Improved technologies for shaping climate resilient decisions and embedding state-of-the-art climate information into the decision workflow are critical for the sustainability of water resources and energy production in the Lake Victoria basin. There is a need for improved high resolution models to capture the specific rainfall patterns on and around the lake, as well as for systematic observations of rainfall and evaporation.