Global Snow and Ice - September 2020

Sea Ice Extent

The sea ice extent data for the Arctic and Antarctic are provided by the National Snow and Ice Data Center (NSIDC) and are measured from passive microwave instruments onboard NOAA Satellites. The sea ice extent period of record is from 1979–2020 for a total of 42 years.

September 2020 Sea Ice Extent
(per decade)
(out of 42 years)
million km2 million mi2 Year(s) million km2 million mi2
Northern Hemisphere 3.92 1.51 -38.85% -12.79% Largest 41st 1980 7.67 2.96
Smallest 2nd 2012 3.57 1.38
Southern Hemisphere 18.77 7.25 +1.51% +0.49% Largest 13th 2014 19.76 7.63
Smallest 30th 1986 17.68 6.83
Globe 22.69 8.76 -8.88% -2.93% Largest 40th 1980 26.49 10.23
Smallest 2nd 2016 22.68 8.76
Ties: 2019

Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2020 (42 years)

The September average Arctic sea ice extent was the second smallest for September in the 42-year record at 2.49 million square km (961,000 square miles), or 38.8 percent, below the 1981–2010 average. This was also 350,000 square km (135,000 square miles) smaller than the record set in September 2012. September 2020 marked the 19th consecutive September with below-average sea ice extent.

On September 15, the Arctic sea ice extent reached its minimum annual extent of 3.74 million square km (1.44 million square miles), which is the second smallest minimum extent on record, behind September 17, 2012. This was also the second time in the 42-year record in which the annual extent dropped below 4.0 million square km (1.54 million square miles). The 14 smallest minimum annual extents have occurred in the last 14 years.

The Antarctic sea ice extent during September 2020 was above average at 18.77 million square km (7.25 million square miles) or 1.51 percent above average. This was the 13th largest September Antarctic sea ice extent in the 42-year satellite record. Accordng to the NSIDC, Antarctica may have reached its annual maximum extent on September 28 when it reached 18.95 million square km (7.32 million square miles).

Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Global Snow and Ice for September 2020, published online October 2020, retrieved on October 24, 2020 from