The curious record of Antarctic sea ice

Data show the extent of sea ice in million square kilometers during the traditionally highest and lowest months of the year (September and February) and as an annual average. September of 2025 saw the third lowest maximum extent on record.

Available data for monthly average sea ice extent in September and February, and annually, begin in 1979. For 1987 and 1988, annual average figures are shown, but each calculation is based on only 11 months of data.
Chart: Chris MooneySource: National Snow and Ice Data CenterCreated with Datawrapper