I think this is the more comprehensive long-term dataset: https://www.ncei.noaa.gov/products/extended-reconstructed-sst https://www.ncei.noaa.gov/products/exte

I think this is the more comprehensive long-term dataset: https://www.ncei.noaa.gov/products/extended-reconstructed-sst https://www.ncei.noaa.gov/products/extended-reconstructed-ss... Note also the most reliable data on this is probably from the Argo floats, there are about 4000 of them deployed globally (collected data besides SST, such as mixed-layer depth, salinity etc.), since 2000: https://argo.ucsd.edu/about/status/ https://argo.ucsd.edu/about/status/