Summary
Arctic sea ice reached an estimated 4.6 million square kilometres on September 12, 2026, tying three other years for the 10th-lowest minimum in the satellite record. The long-term decline continues even as recent summer minimums have been relatively steady.
NASA says Arctic sea ice reached its annual minimum on September 12, 2026, covering an estimated 4.6 million square kilometres (1.78 million square miles). That ties 2008, 2010 and 2025 for the 10th-lowest minimum in the satellite record. The summer low is part of a longer decline: satellite observations show that Arctic sea ice covers less of the ocean at both its annual minimum and maximum than it did several decades ago.
A low within a long-term decline
Sea ice grows during the Arctic winter, usually reaching its maximum in March, then retreats through summer to a minimum in September. The seasonal cycle is natural, but the overall direction has changed. Satellites have recorded the annual growth and retreat continuously since late 1978, and the long-term trend has been downward. NASA reports that the decline steepened in the 2000s.
Every summer from 2007 through 2026 ranks among the 20 lowest minimum extents in the satellite record. The lowest was in September 2012. In recent years, September extent has been relatively steady, but it remains well below the long-term average. Weather can influence how much ice melts in an individual summer; NASA scientists say increased cloud cover over the past decade has reduced the sunlight available to accelerate melting.
The winter maximum is also reaching historic lows. The March 2026 maximum statistically tied with March 2025 for the lowest in the satellite record. The ice that remains is changing as well: observations show a decline in multiyear ice, which survives at least one summer melt season, leaving more of the Arctic covered by thinner first-year ice.
Natural variability, including the Arctic Oscillation, affects sea-ice extent from year to year. NASA says that variability cannot alone explain the decline seen across the satellite record; natural variation and rising global temperatures have contributed together to greater ice loss. Scientists project that the Arctic could experience an essentially ice-free condition at least once before the middle of the 21st century.
How satellites track the ice
Passive microwave sensors measure microwave energy naturally emitted by Earth. Sea ice emits more of this energy than open water, allowing satellites to distinguish the two. Because microwaves pass through clouds, the observations can be collected regularly regardless of weather.
The record began with data from NASA’s Nimbus-7 satellite in 1978. Defense Meteorological Satellite Program satellites contributed observations from 1987, and NASA’s Aqua satellite from 2002 to 2011. Since 2025, scientists have also used observations from Japan’s GCOM-W satellite. A small region around the North Pole has historically been outside the sensors’ coverage; NASA says the sea-ice estimates assume that this area is ice-filled.