The timing and mechanisms of past hydroclimate change in many regions of the tropics are poorly constrained, limiting our ability to evaluate climate model performance. Proxy records of past hydroclimate can provide critical information about the dynamical drivers of regional precipitation variability, and contribute to improved climate projections, yet the existing data is sparse in space and time. Filling these gaps can contribute to evaluation and improvement of climate models, by helping to: 1) Constrain the magnitude and timing of precipitation change in response to external forcings and internal ocean-atmosphere variability , 2) Evaluate the spatial pattern of regional precipitation changes in models, and 3) Provide robust data for proxy-model comparison studies, which may help reveal model biases. Speleothems are ideally suited archives of past hydroclimate due to their precise U-Th based age models and the multiple hydrologically sensitive proxies they contain. In this talk, I will present multi-proxy hydroclimate records from our field sites in Mexico, Laos, and Vietnam, and discuss how we combine cave monitoring, proxy system modeling, instrumental climate data, and isotope-enabled climate model output to investigate the dynamics of hydroclimate variability on interannual to orbital timescales.