Arctic sea ice reached its annual minimum extent on Sept. 12, 2026, covering an estimated 1.78 million square miles (4.6 million square kilometers), according to NASA and the National Snow and Ice Data Center at the University of Colorado Boulder. The figure ties 2008, 2010 and 2025 for the 10th-lowest minimum in the satellite record, the agencies reported on Sept. 23. NASA said the past 20 years, from 2007 through 2026, produced the 20 lowest annual Arctic minimum extents since continuous satellite measurements began in late 1978.

NSIDC senior research scientist Walt Meier said the extent has plateaued but remains low relative to the earlier part of the record. NASA's Linette Boisvert attributed relatively stable September extents in recent years partly to increased cloud cover limiting how much solar radiation accelerates melt.

At the other pole, Antarctic sea ice was approaching its annual maximum after declining by roughly 116,000 square miles (300,000 square kilometers) over six days in August, then resuming growth. Meier linked the decline to weather pushing and compacting thin ice near the outer edge, calling its magnitude unusual. Both scientists remained cautious about describing Antarctic change as a long-term trend.