The CalCOFI SIO Hydrographic Bottle Data dataset provides an extensive collection of hydrographic measurements from the California Cooperative Oceanic Fisheries Investigations (CalCOFI) program, spanning from 1949 to 2021. This dataset, managed by the Scripps Institution of Oceanography (SIO), includes critical oceanographic variables such as water temperature, salinity, oxygen levels, and chlorophyll-a concentrations. The data are collected using Niskin bottles during oceanographic casts, providing detailed vertical profiles at numerous stations across the California Current System.