PRISM3D uses multiple proxies to develop February and August synoptic reconstructions of the surface ocean. Planktonic foraminiferal assemblages were translated to February and August surface temperatures via factor analytic transfer function and the modern analog technique. Mg/Ca and alkenone paleothermometry were incorporated as supplementary data for the first time in a PRISM reconstruction. Individual time series were calibrated to age using a combination of magnetobioisostratigraphy, and warm peaks within the PRISM interval were averaged.These warm peak averages for February and August form the basic data used to produce contour maps of mid-Pliocene SST. Wherever other proxy data were available, they were plotted and interpreted within the context of the faunal February and August estimates (which were assumed to represent seasonal extremes). In almost all cases, alkenone, Mg/Ca and faunal estimates showed realistic results given the fact that each proxy represents a different aspect of the paleoenvironment. PRISM3D monthly SST fields are presented on a 2 x 2 latitude x longitude grid. SSTs for the remaining 10 months of the year were derived by fitting a sine curve to the February and August SST estimates.