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Antarctic sea ice has likely reached its maximum extent for the year, at 17.81 million square kilometers (6.88 million square miles) on September 17, according to scientists at the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder (CU Boulder). The 2025 maximum is the third lowest in the 47-year satellite record. The record low maximum occurred in 2023.

On September 17, Antarctic sea ice likely reached its annual maximum extent of 17.81 million square kilometers (6.88 million square miles). The 2025 maximum is the third lowest in the 47-year satellite record above 2023 and 2024.

On September 10, Arctic sea ice likely reached its annual minimum extent of 4.60 million square kilometers (1.78 million square miles). The 2025 minimum shares the tenth lowest spot in the nearly 47-year satellite record with 2008 and 2010.

In August, sea ice rapidly melted and compacted north of Alaska in the Beaufort Sea, initiated by a warm pulse of air from east Siberia that was sustained by persistent winds from the southwest. However, the overall pace of decline for the month was near average. Antarctic sea ice climbed in August but remained well below average, ending at third lowest extent.

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