The maps below show the extent of sea ice in the Northern Hemisphere around the North Pole. Select a month and year from the popup menus to compare two maps side-by-side.

Try this:

  • compare the sea ice in March and September for the same year
  • compare the sea ice in March for two different years
  • compare the sea ice in September for two different years
  • explore sea ice extent in the Southern Hemisphere (around Antarctica)

Arctic Sea Ice Extent in March 2018

Arctic Sea Ice Extent in September 2018

Map images and sea ice data courtesy of the National Snow and Ice Data Center (NSIDC). Interactive created by Randy Russell, UCAR Center for Science Education.

In the Northern Hemisphere (around the North Pole and the Arctic Ocean) the sea ice reaches its maximum extent in early spring, at the end of the long, cold winter. March is usually the month with the most sea ice.

The ice pack melts and breaks up over the summer. September is usually the month with the least amount of sea ice (in the Northern Hemisphere).

The Northern Hemisphere ice pack is shrinking as a result of climate change. The average rate of decrease in the extent of the ice pack in September between 1979 and 2018 was 12.8% per decade (± 2.3%).

The pink line in the images shows the average (from 1981 to 2010) edge of the ice pack for a particular month.

To extend your learning: