Data
Arctic sea ice extent in September (NSIDC)
Mean extent of Arctic sea ice in September, the month of the yearly minimum, since 1979: the area of ocean where satellites measure at least 15% ice cover, from NSIDC's Sea Ice Index. From 2025 NSIDC uses JAXA's AMSR2 satellite record instead of the DMSP record.
Latest value
4.81million km²
Northern Hemisphere oceans (the Arctic Ocean and surrounding seas), September 2026. Version 4.0.
Arctic sea ice extent in September (NSIDC) (million square kilometres)
Show as a table
| Period | Value (million km²) | Status |
|---|---|---|
| 1979-09 | 7.05 | final |
| 1980-09 | 7.67 | final |
| 1981-09 | 7.14 | final |
| 1982-09 | 7.30 | final |
| 1983-09 | 7.39 | final |
| 1984-09 | 6.81 | final |
| 1985-09 | 6.70 | final |
| 1986-09 | 7.41 | final |
| 1987-09 | 7.28 | final |
| 1988-09 | 7.37 | final |
| 1989-09 | 7.01 | final |
| 1990-09 | 6.14 | final |
| 1991-09 | 6.47 | final |
| 1992-09 | 7.47 | final |
| 1993-09 | 6.40 | final |
| 1994-09 | 7.14 | final |
| 1995-09 | 6.08 | final |
| 1996-09 | 7.58 | final |
| 1997-09 | 6.69 | final |
| 1998-09 | 6.54 | final |
| 1999-09 | 6.12 | final |
| 2000-09 | 6.25 | final |
| 2001-09 | 6.73 | final |
| 2002-09 | 5.83 | final |
| 2003-09 | 6.12 | final |
| 2004-09 | 5.98 | final |
| 2005-09 | 5.50 | final |
| 2006-09 | 5.86 | final |
| 2007-09 | 4.27 | final |
| 2008-09 | 4.69 | final |
| 2009-09 | 5.26 | final |
| 2010-09 | 4.87 | final |
| 2011-09 | 4.56 | final |
| 2012-09 | 3.57 | final |
| 2013-09 | 5.21 | final |
| 2014-09 | 5.22 | final |
| 2015-09 | 4.62 | final |
| 2016-09 | 4.53 | final |
| 2017-09 | 4.82 | final |
| 2018-09 | 4.79 | final |
| 2019-09 | 4.36 | final |
| 2020-09 | 4.00 | final |
| 2021-09 | 4.95 | final |
| 2022-09 | 4.90 | final |
| 2023-09 | 4.38 | final |
| 2024-09 | 4.35 | final |
| 2025-09 | 4.75 | final |
| 2026-09 | 4.81 | final |
Notes on individual values
- NSIDC's file gives the source data set as NSIDC-0803: JAXA's AMSR2 record, the input from 1 January 2025 (earlier years use the DMSP passive microwave record, NSIDC-0051).
Where it comes from
- Producer
- NOAA@NSIDC, National Snow and Ice Data Center (CIRES, University of Colorado Boulder) · Sea Ice Index, Version 4 (G02135)
- Version
- 4.0
- Fetched
- 2026-10-05 (automatically), 2,352 bytes
- Fingerprint
- sha256 3968dfdbe73b8361712da9136cfeff6dbc9a6d87ab3e75daa30cc254615eab1fETag "6abfb390-930" · Last-Modified Fri, 02 Oct 2026 13:37:20 GMT
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Fetterer, F., Knowles, K., Meier, W. N., Savoie, M., Windnagel, A. K. & Stafford, T. (2025). Sea Ice Index. (G02135, Version 4). [Data Set]. Boulder, Colorado USA. National Snow and Ice Data Center. https://doi.org/10.7265/a98x-0f50. Daily and monthly sea ice extent, Northern and Southern Hemispheres. Date Accessed 2026-10-05.
What was done to it
Read the extent column of N_09_extent_v4.0.csv, NSIDC's Northern Hemisphere September file (one row per year, 1979 to 2026), as printed in million km². NSIDC computes each value as the mean of the month's daily extents (cells with at least 15% ice concentration, the unobserved area around the pole counted as ice covered).
Code: pipeline/src/envdash/transforms/ice/nsidc_sea_ice.py · code sha256 8b0c8ba6e2a25c09… · inputs 3968dfdbe73b…
Rows whose source data set is NSIDC-0803 (JAXA's AMSR2 record, used from 1 January 2025) carry that as a note.
Code: pipeline/src/envdash/transforms/ice/nsidc_sea_ice.py · code sha256 8b0c8ba6e2a25c09… · inputs 3968dfdbe73b…
What it covers
- Geography
- Northern Hemisphere oceans (the Arctic Ocean and surrounding seas)
- Basis
- Sea ice extent: mean over the month of the daily area of grid cells with at least 15% ice concentration (25 km grid, passive microwave), the unobserved area around the pole counted as ice covered. Not sea ice area, and not OSI SAF's index.
- Unit
- million square kilometres (million km²)