The Global Precipitation Climatology Project (GPCP) under the auspices of GEWEX has developed global precipitation data sets at monthly, pentad, and daily time scales. In addition to these official products, an experimental 3-hourly data set is under development drawing on a high-resolution global array of infrared observations. While the original intent of the GPCP data was to provide globally complete coverage for large-scale climate investigations such as El Niņo, the direction of data set development towards finer time and space scales has led to new applications in regional climatology and hydrology. An important application for the GPCP data sets is in the Pan American sector. The primary rainmaking systems in this region have their origin over the oceans. Central America is dominated by the eastern Pacific Intertropical Convergence Zone (ITCZ), monsoonal rainfall affects Mexico, and Northeast Brazil relies on the Atlantic ITCZ. This part of the world is also strongly influenced by the El Niņo / Southern Oscillation (ENSO). While the climatology and interannual variability of rainfall in the Pan American region has been described over land, questions remain as to the progression of rainfall systems onshore. For example, convectively-coupled Kelvin waves may be a trigger mechanism for the onset of the Mexican monsoon. In this paper we begin to examine these issues with hourly to daily GPCP and Tropical Rainfall Measuring Mission (TRMM) precipitation products and other supporting data sets (e.g. SST and surface winds), with a focus on the eastern Pacific, equatorial Atlantic, and Caribbean Sea.