Page Overview & Data Sources

• This page provides time series and map visualizations of monthly mean Sea Surface Temperature (SST) from NOAA Optimum Interpolation SST (OISST) version 2.1. OISST is a 0.25°x0.25° gridded dataset that provides estimates of temperature based on a blend of satellite, ship, and buoy observations for the period September 1981 to present. The SST anomalies shown on this page are from the anomaly variable in the OISST dataset, which is based on 1971–2000 climatology. Learn more about the OISST, including strengths and limitations, from the NCAR Climate Data Guide.


• The time series chart displays area-weighted means for the selected region (see buttons located below the chart. For example, if World 60°S-60°N is selected, then each daily SST value on the chart represents the average of all ocean gridcells between 60°S and 60°N across all longitudes, and accounts for the convergence of longitudes at the poles. The map below the chart can be updated by either moving the Image Slider or by hovering the cursor over values in on the time series chartclicking a point on one of the time series. The map and chart can be switched between SST and SST anomaly from the variable dropdown menu. A sea ice mask is applied to the SST and anomaly maps for gridcells where ice concentration is >= 50%.


• Any apparent record high monthly temperatures in OISST should be evaluated against other datasets. For long-term global climate time series, refer to NOAA's National Centers for Environmental Information (NCEI) Climate at a Glance with monthly means of surface temperature observations 1850 to present.


• NCAR Command Language is used for data processing and map generation. The interactive time series chart is made using HighCharts. OISST data grids can be downloaded from NCEI here.

Last updated 7 January 2024