Global Snow and Ice - December 2020

NH Snow Cover Extent

December 2020 Snow Cover Extent 1981-2010 Anomaly Trend
(per decade)
Rank
(out of 55 years)
Records
million km2 million mi2 million km2 million mi2 million km2 million mi2 Year(s) million km2 million mi2
Northern Hemisphere 43.70 16.87 -0.28 -0.11 +0.33 +0.13 Largest 32nd 2012 46.85 18.09
Smallest 24th 1980 37.44 14.46
North America 16.50 6.37 -0.35 -0.14 +0.11 +0.04 Largest 36th 2009 18.27 7.06
Smallest 20th 1980 14.56 5.62
Eurasia 27.20 10.50 +0.07 +0.03 +0.22 +0.08 Largest 26th 2002 29.70 11.47
Smallest 30th 1980 22.88 8.83

Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1966–2020 (55 years)

The Northern Hermisphere snow cover extent for December 2020 was near average at 43.70 million square km (16.87 million square miles). This value is 280,000 square km (110,000 square miles) below the 1981–2010 average and the 24th smallest December snow cover extent in the 55-year record.

The North American snow cover extent was 350,000 square km (140,000 square miles) below average, resulting in the 20th smallest December extent on record. Above-average December 2020 was limited to parts of southwestern and southeastern Canada, the northeastern contiguous U.S., and across the southern Rocky Mountains. Meanwhile, below-average snow cover extent was observed across parts of the northern and southwestern contiguous U.S. Canada, and the contiguous U.S. were slightly below average. Alaska snow cover extent for December 2020 tied for the largest December snow cover extent on record.

Eurasia's December 2020 snow cover extent was near average at 27.20 million square km (10.50 million square miles). Above-average snow cover extent was observed across parts of southern Khazakstan, southern Mongolia, northern China, and across central Asia. Below-average December snow cover extent was observed across Europe and southern China.


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.

December 2020 Sea Ice Extent
1981-2010
Anomaly
Trend
(per decade)
Rank
(out of 42 years)
Records
million km2 million mi2 Year(s) million km2 million mi2
Northern Hemisphere 11.77 4.54 -8.33% -3.50% Largest 39th 1982 13.64 5.27
Smallest 3rd 2016 11.46 4.42
Southern Hemisphere 10.44 4.03 +0.29% +0.58% Largest 18th 2007 11.98 4.63
Smallest 24th 2016 8.28 3.20
Globe 22.21 8.58 -4.47% -1.68% Largest 35th 1988 24.69 9.53
Smallest 7th 2016 19.74 7.62

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

December 2020 Arctic sea ice extent was the third smallest on record at 11.77 million square km (4.54 million square miles). This was 8.33% below the 1981–2010 average. Only Decembers of 2016 and 2017 had a smaller December extent. This was also the 23rd consecutive December with below-average sea ice extent. According to NSIDC, sea ice was below average in the Bering and Barent seas.

After four consecutive years of below-average sea ice extent, Antarctic's sea ice extent during December was near average at 10.44 million square km (4.03 million square miles).


Citing This Report

NOAA National Centers for Environmental Information, State of the Climate: Global Snow and Ice for December 2020, published online January 2021, retrieved on February 28, 2021 from https://www.ncdc.noaa.gov/sotc/global-snow/202012.

Metadata