Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Arctic Sea Ice at Maximum Extent for 2021


Arctic sea ice has likely reached its maximum extent for the year, at 14.77 million square kilometers (5.70 million square miles) on March 21, 2021, according to scientists at the National Snow and Ice Data Center (NSIDC). The 2021 maximum is tied with 2007 for seventh lowest in the 43-year satellite record. 

Please note that the Arctic sea ice extent number is preliminary—continued winter conditions could still push the ice extent higher. NSIDC will issue a formal announcement at the beginning of April with full analysis of the possible causes behind this year’s ice conditions, interesting aspects of the growth season, the set up going into the summer melt season ahead, and graphics comparing this year to the long-term record.

For more details and images, please see the NSIDC Arctic Sea Ice News & Analysis page.

NSIDC is part of CIRES at CU Boulder. The NSIDC Arctic Sea Ice News & Analysis is supported in part by NASA.


CIRES is a partnership of NOAA and CU Boulder.