Sea ice, both poles, 1979–2026
The ice at both ends of the Earth
Each disc is a calendar. Each ring is a year, from 1979 at the centre to 2026 at the edge; each slice is a day, with January at the top. Blue means more sea ice than the 1981–2010 normal for that day, orange and red less.
Your day
Pick any date from 1979 to 11 November 2026: the day you were born, a winter you remember. The extent is compared with the normal for the same day of the year, and the difference is given in Romanias.
The Arctic: the summer low has halved
Sea ice is frozen sea water that floats. It grows each winter and shrinks each summer. In the Arctic it is smallest in September. In 1979 the September low was 6.94 million square kilometres. In 2012 it was 3.39 million, on 17 September, the lowest on record and less than half.
Every September low since 1997 has been below 1979's. On its worst day compared with normal, 23 October 2020, it was 3.68 million square kilometres short: an area 15 times the size of Romania.
Arctic: the lowest day of each year (million km²)
Antarctica: decades of nothing, then a fall
Around Antarctica the sea ice is largest in September and smallest in February. For more than 35 years it stayed close to normal, and in September 2014 it reached a record high of 20.16 million square kilometres. Then, from 2016, it dropped, and in 2023 it fell further than ever recorded.
In February 2023 the summer low was 1.85 million square kilometres, the lowest on record. That winter it never recovered: the September high was 17.07 million, also a record low. On 7 July 2023 it was 2.82 million square kilometres short of normal, an area nearly 12 times the size of Romania.
Antarctica: the highest day of each year (million km²)
How it is measured
Satellites read the microwaves the surface gives off, which differ between ice and open water. Extent is the area of all the 25-kilometre squares where at least 15 percent of the sea is covered with ice. Until 1987 the satellite measured every other day, so the inner rings are built from half the days, and a few weeks in 1987 and 1988 are missing.
On 11 November 2026, the last day here, the Arctic had 8.84 million square kilometres of sea ice against a normal of 10.42, and Antarctica 15.09 million against 16.57. Both were short by about one and a half million square kilometres, more than six times the size of Romania each.
Sources
All of the ice data is from NSIDC's Sea Ice Index, downloaded on 13 November 2026.
- F. Fetterer, K. Knowles, W. N. Meier, M. Savoie, A. K. Windnagel and T. Stafford, Sea Ice Index, version 4 (G02135), NSIDC: National Snow and Ice Data Center, daily extent for both hemispheres, 26 October 1978 to 11 November 2026, and the 1981–2010 daily median; accessed 13 November 2026.
- NSIDC, About the data and the version 4 user guide: extent is every 25 km cell with at least 15% ice; the satellite before August 1987 scanned on alternate days; the area around the North Pole that is not imaged is counted as ice. Records on this page are five-day trailing averages, as NSIDC reports them, from the current version of the data, so they can differ slightly from figures announced at the time. DOI 10.7265/a98x-0f50.
- Romania's area, 238,397 km²: National Institute of Statistics (INS), Romanian Statistical Yearbook 2017, table 1.8.