Page Overview & Data Sources

• This page provides time series and map visualizations of daily 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. The datset spans 1 September 1981 to present with a 1 to 2-day lag from the current day. Data are preliminary for about two weeks until a finalized product is posted by NOAA. This status is identified on the maps by "preliminary" appearing in the title, and applies to the time series as well. SST anomalies, which are included in the OISST dataset, are 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 domain. For example, if World 60S-60N 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. Hide or display individual time series by clicking the year below the chart; Hide All and Show All buttons are at the chart lower right. The map below the chart can be updated by clicking a point on one of the time series. The map can be switched between SST and SST anomaly by clicking the toggle botton at the map top-left. A sea ice mask is applied to the SST and anomaly maps for gridcells where ice concentration is >= 50%.


• Monthly OISST visualizations are available on Climate Reanalyzer here.


• Please note that any apparent record high daily temperature 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 are downloaded from NCEI here.

Last updated 10 December 2023