Precipitation data sets, referred to as "products", are available at a variety of levels which denote the amount of processing that data has been through. These range from the raw instrument data to precipitation model outputs which are mathematically derived using the raw data as an input.
The below tables provide descriptions and links for all of the primary sources available for downloading GPM and TRMM data. The products are first arranged by mission (GPM or TRMM), then by data processing level (the tabs at the top of the table). You can then select your desired algorithm from the list to view details about the algorithm, resolution, region, latency, and a list of links to download the data.