A layer of frozen seawater caps the Arctic Ocean, growing through the long polar winter and melting through the summer to its annual low in September. This natural fluctuation has persisted for millennia, but satellite records show the ice now covers less of the Arctic Ocean at both its annual maximum and minimum than it did a few decades ago.
In 2026, sea ice reached its minimum extent on September 12, according to NASA's Earth Observatory. The extent tied several past years for the 10th-lowest minimum in the satellite record. An accompanying map shows September 2026 sea ice covering a smaller area than the 1981–2010 median, outlined in yellow.
The data comes from the National Snow and Ice Data Center and continues a long-term decline observed since satellite measurements began in the late 1970s. The Arctic sea ice minimum is closely watched as a key indicator of climate change.