Antarctic sea ice likely reached 2026 maximum, third-lowest

Antarctic sea ice likely reached its annual maximum extent on 2026-09-14. The event is ranked as the third-lowest maximum on record.

The annual maximum extent was likely reached on 2026-09-14. The facts give the coverage as 17,590,000 square kilometers, or 6,790,000 square miles, and rank the maximum as third-lowest on record.

The seasonal reference months listed are September and February, and the maps cited cover 1990 to 2026.

From 1979 to 2014, total Antarctic sea ice had a 1 percent per decade increase, but the facts state uncertainty over whether that change was meaningful. The increase ended, significant decreases started, and coverage has largely remained lower than normal. Both a record low minimum and a record low maximum are listed for 2023, and the decline is under observation.

Measurements rely on passive microwave sensors, because sea ice produces a stronger microwave signal than open water. Satellites can monitor sea ice regardless of weather.

The sea ice record includes 1978 and Nimbus-7, along with Defense Meteorological Satellite Program (DMSP) satellites in 1987, NASA's Aqua satellite from 2002 to 2011, and JAXA's GCOM-W satellite in 2025.

NASA Earth Observatory images use National Snow and Ice Data Center data and list Michala Garrison. The World of Change item was announced 2026-10-06, and the National Snow and Ice Data Center announced on 2026-09-23 that the Antarctic maximum most likely had been reached.

For lunar-industry readers, NASA and JAXA appear in these sea ice facts through NASA Earth Observatory images, NASA's Aqua satellite and JAXA's GCOM-W satellite.

The facts also show satellite observations linked to 1978, using passive microwave sensors that can distinguish ice from open water and work regardless of weather.