This data set comprises 43 sets of annualised timeseries, including Plankton Colour Index (PCI) and 22 simultaneously measured plankton abundance timeseries, and seasonal cloud cover, salinity, sea surface temperature, and wind speed, for 26 areas of British seas recorded between 1958 and 2013 inclusive. Data was obtained, aggregated and annualised as described in Synchrony is more than its top-down and climatic parts: interacting Moran effects on phytoplankton in British seas 10.1371/journal.pcbi.1006744 The 26 numbered areas of sea are identified in that paper (supplementary figure 4). In the case of PCI or plankton timeseries, files are annual average values dominated by the fluctuations in annual bloom size. Plankton abundance timeseries are named by species. In the case of the physical/oceanographic variables, each timeseries represents a seasonal average, and the files are named after the variable and the month numbers being averaged over in each case. For example, cloud3to5.csv is an average of monthly cloud values for March to May inclusive. Data was exported using matlab as a csv numeric table, recorded up to 5 significant digits. The first column of each table gives area identification numbers, the top row of each table gives year values, the top corner value is left blank (0). Data compiled and exported by Lawrence W Sheppard (lwsheppard@ku.edu)