Ocean · sea ice
The poles breathe
The last year of NSIDC daily measurements replayed fast: Arctic ice melts in the boreal summer while Antarctic ice expands, then the reverse.
- Date
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- Arctic
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- Antarctic
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Arctic, latest day
6.72 10⁶ km²
Antarctic, latest day
16.20 10⁶ km²
Both poles
22.92 10⁶ km²
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Cap with the same area as the measured extent (the real edge is not a circle); NSIDC Sea Ice Index v3.
Arctic, latest day
6.72 10⁶ km²
2026-10-17
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Antarctic, latest day
16.20 10⁶ km²
2026-10-17
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Lowest Arctic daily extent of the series
3.34 10⁶ km²
2012-09-16
record: 17 September 2012
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Lowest Antarctic daily extent of the series
1.85 10⁶ km²
2023-02-21
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Daily extent, last three years
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Show the data as a table
Yearly minimum of Arctic extent
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Show the data as a table
Yearly minimum of Antarctic extent
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Show the data as a table
Monthly means since 1978
Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC) · NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · 10/23/26
Show the data as a table
Method and sources
The NSIDC Sea Ice Index derives sea ice extent from passive microwave radiometers (SMMR, SSM/I, SSMIS, AMSR2) with the NASA Team algorithm; extent counts pixels with at least 15% concentration. The v4 daily files are read as published.
Yearly minima and monthly means are computed on the server.
Reading these data
Extent is neither volume nor thickness; sensor changes are homogenised by NSIDC but some uncertainty remains. Arctic and Antarctic trends differ and are not explained by the same mechanisms.
SOURCES OF THIS PAGE
- Sea Ice Index v4, Northern Hemisphere daily extent (NSIDC)
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Fetterer, F., Knowles, K., Meier, W. N., Savoie, M., & Windnagel, A. K. (2017, updated daily). Sea Ice Index, Version 4 (G02135), Northern Hemisphere daily extent. NSIDC.
· doi:10.7265/N5K072F8 · source page ↗
Licence : NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · retrieved on Oct 23, 2026 · SHA-256 d36fc1791ba9… - Sea Ice Index v4, Southern Hemisphere daily extent (NSIDC)
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Fetterer, F., Knowles, K., Meier, W. N., Savoie, M., & Windnagel, A. K. (2017, updated daily). Sea Ice Index, Version 4 (G02135), Southern Hemisphere daily extent. NSIDC.
· doi:10.7265/N5K072F8 · source page ↗
Licence : NSIDC data, free with citation (Fetterer et al., 2017, updated daily) · retrieved on Oct 23, 2026 · SHA-256 824c6aff3c2e… - Fetterer, F., Knowles, K., Meier, W. N., Savoie, M., & Windnagel, A. K. (2017, updated daily). Sea Ice Index, Version 3. NSIDC: National Snow and Ice Data Center.
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Fetterer, F., Knowles, K., Meier, W. N., Savoie, M., & Windnagel, A. K. (2017, updated daily). Sea Ice Index, Version 3. NSIDC: National Snow and Ice Data Center.
· doi:10.7265/N5K072F8
Licence : Published literature; cited