NOAA's National Centers for Environmental Information
Northern Hemisphere Snow Cover Extent
| May 2024 | Snow Cover Extent | Anomaly 1991-2020 | Trend per decade | Rank (58 years) | Record | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | million km² | million mi² | million km² | million mi² | Year(s) | million km² | million mi² | |||
| Northern Hemisphere | 17.13 | 6.61 | -1.09 | -0.42 | -0.77 | -0.30 | Largest | 45th | 1974 | 23.09 | 8.92 |
| Smallest | 14th | 2010 | 15.38 | 5.94 | |||||||
| North America | 8.10 | 3.13 | -0.94 | -0.36 | -0.25 | -0.10 | Largest | 53rd | 1974 | 11.48 | 4.43 |
| Smallest | 6th | 2023 | 7.47 | 2.88 | |||||||
| Eurasia | 9.04 | 3.49 | -0.14 | -0.05 | -0.52 | -0.20 | Largest | 40th | 1976 | 12.51 | 4.83 |
| Smallest | 19th | 2013 | 7.26 | 2.80 | |||||||
Data Source: Global Snow Laboratory, Rutgers University. Period of record: 1967–2024 (58 years)
The Northern Hemisphere snow cover extent for May 2024 was 17.13 million square kilometers (6.61 million square miles), which was 1.09 million square kilometers (420,000 square miles) below the 1991–2020 average.
This ranked as the 14th smallest Northern Hemisphere May snow extent on record. Snow extent for May has been below average in 13 of the past 15 years. The downward linear trend in May Northern Hemisphere snow cover extent over the 58-year record equates to an average reduction of 77,000 square kilometers (30,000 square miles) of snow cover extent per year.
The North America and Greenland snow cover extent was 8.10 million square kilometers (3.13 million square miles), which was 940,000 square kilometers (360,000 square miles) below the 1991–2020 average. This ranked as the sixth smallest May snow cover extent on record for North America, but was 630,000 square kilometers (250,000 square miles) greater than last year's record low May snow cover extent. Although the May snow-covered area was above average in the western U.S., below-average snow cover extent was present across most of North America. Small areas of above-average snow cover extent are visible in parts of the U.S. and Canadian Rocky Mountains, the Sierra Nevada mountains, the Yukon territory of Canada, and parts of Alaska.
Snow cover extent over Eurasia in May was near average at 9.04 million square kilometers (3.49 million square miles), which was 140,000 square kilometers (50,000 square miles) below the 1991–2020 average. This was the 19th-smallest May snow cover extent on record for Eurasia.
May snow cover extent was above-average across a large part of western Siberia, far eastern Russia, and a large part of central China. Below-average snow cover extent was present across large parts of the eastern half of Russia, and areas that included parts of western China, Nepal, northern Afghanistan, and Kyrgyzstan.
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 1979–2024 for a total of 46 years.
| May 2024 | Sea Ice Extent | Anomaly 1991-2020 | Trend per decade | Rank (46 years) | Record | ||||
|---|---|---|---|---|---|---|---|---|---|
| million km² | million mi² | Year(s) | million km² | million mi² | |||||
| Northern Hemisphere | 12.78 | 4.93 | -1.16% | -2.32% | Largest | 35th | 1985 | 14.07 | 5.43 |
| Smallest | 13th | 2016 | 11.92 | 4.60 | |||||
| Ties: 2007 | |||||||||
| Southern Hemisphere | 9.27 | 3.58 | -9.91% | -0.10% | Largest | 42nd | 2015 | 11.72 | 4.53 |
| Smallest | 5th | 2023 | 8.36 | 3.23 | |||||
| Globe | 22.05 | 8.51 | -5.04% | -1.38% | Largest | 40th | 1982 | 24.73 | 9.55 |
| Smallest | 7th | 2019 | 21.04 | 8.12 | |||||
Data Source: National Snow and Ice Data Center (NSIDC). Period of record: 1979–2024 (46 years)
Globally, May 2024 sea ice extent was seventh smallest in the 46-year May record at 22.05 million square kilometers (8.51 million square miles). This was approximately 1.17 million square kilometers (460,000 square miles) less than the 1991–2020 average, but above last year's second lowest May extent of 21.19 million square kilometers (8.18 million square miles).
The average Arctic sea ice extent for May 2024 tied as the 12th smallest in the satellite record at 12.78 million square kilometers (4.93 million square miles). This was approximately 150,000 square kilometers (60,000 square miles) below the 1991–2020 average. The average May Arctic sea ice extent has been at least nominally below the 1991–2020 average in each of the past 11 years.
May sea ice extent was near to below average in Baffin Bay, the Gulf of Saint Lawrence, and the Sea of Okhotsk, and Hudson Bay had its lowest May sea ice extent on record, tied with 2021. Sea ice extent was near to above average in the Barents Sea, the Bering Sea, and the Greenland Sea. May sea ice extent also was above average in the Sea of Japan.
The average Antarctic sea ice extent for May 2024 was the fifth smallest on record (9.27 million square kilometers or 3.58 million square miles), approximately 1.02 million square kilometers (390,000 square miles) below the 1991–2020 average. This year's May extent was approximately 910,000 square kilometers (350,000 square miles) greater than May 2023, which was the smallest May extent on record. The average May Antarctic sea ice extent has been below the 1991–2020 average in eight of the past nine years.