On September 17, Antarctic sea ice likely reached its annual maximum extent of 17.81 million square kilometers (6.88 million square miles). The 2025 maximum is the third lowest in the 47-year satellite record above 2023 and 2024.
Please note that this is a preliminary announcement. Changing winds or late-season growth could still increase the Antarctic ice extent as happened in 2002 and 2017.
Overview of Conditions
On September 17, 2025, Antarctic sea ice extent likely peaked with a maximum of 17.81 million square kilometers (6.88 million square miles), the third lowest maximum in the satellite record that began in 1979 (Figure 1a). This year’s extent is 740,000 square kilometers (286,000 square miles) above 2023, the record low maximum. It is 900,000 square kilometers (348,000 square miles) below the 1981 to 2010 average Antarctic maximum extent. Sea ice extent is markedly below average in the Indian Ocean and the Bellingshausen Sea (Figure 1b). Extent is slightly above average stretching out of the Ross Sea.
The Antarctic maximum extent is six days earlier than the 1981 to 2010 median date of September 23. The interquartile range for the date of the Antarctic maximum is September 18 to September 30.
Figure 1a. The graph above shows Antarctic sea ice extent as of September 17, 2025, along with daily ice extent data for four previous years and 2014, the year of the record maximum. 2025 is shown in blue, 2024 in green, 2023 in orange, 2022 in brown, 2021 in magenta, and 2014 in dashed brown. The 1981 to 2010 median is in dark gray. The gray areas around the median line show the interquartile and interdecile ranges of the data. Sea Ice Index data. — Credit: National Snow and Ice Data Center
Figure 1b. Antarctic sea ice extent for September 17, 2025, was 17.81 million square kilometers (6.88 million square miles). The orange line shows the 1981 to 2010 average extent for that day. Sea Ice Index data. About the data — Credit: National Snow and Ice Data Center
Ten lowest maximum Antarctic sea ice extents (satellite record, 1979 to present)
RANK | YEAR | MAXIMUM ICE EXTENT | DATE | |
|---|---|---|---|---|
| IN MILLIONS OF SQUARE KILOMETERS | IN MILLIONS OF SQUARE MILES | |||
1 | 2023* | 17.07 | 6.59 | Sept. 9 |
2 | 2024* | 17.26 | 6.66 | Sept. 16 |
3 | 2025 | 17.81 | 6.88 | Sept. 17 |
4 | 1986 | 17.99 | 6.95 | Sept. 21 |
5 | 2002 | 18.05 | 6.97 | Oct. 12 |
6 | 2017 | 18.10 | 6.99 | Oct. 10 |
7 | 1989 | 18.22 | 7.03 | Sept. 25 |
Values within 40,000 square kilometers (15,000 square miles) are considered tied.
*The 2023 and 2024 values have changed when final analysis data updated near-real-time data. The 2023 extent changed from 16.96 to 17.07 million square kilometers (6.55 to 6.59 million square miles) and the date of the maximum moved from September 10 to September 9. The 2024 extent changed from 17.16 to 17.26 million square kilometers (6.63 to 6.66 million square miles) and the date of the minimum moved from September 19 to September 16.