After a sub-par March maximum, by end of May 2025 Arctic ice closed the gap with the 19-year average.  In mid-August MASIE showed the Arctic ice extent matching the 19-year average.  Mid month Arctic ice went above average and remained in surplus, ranging from a high of +231k km2 to +160k km2 at end of August. Now during the annual minimum month of September 2025 there is  Arctic ice aplenty.

During the annual dip in Arctic ice extent, the average year since 2006 is lowest on day 260 at 4.53M km2.  It then rises to 4.8M km2 ten days later.  The cyan line shows 2025 above average throughout, its lowest extent at 4.85M km2 on day 265, and now up to 5.07M km2.  SII v.4 was lower than MASIE throughout, but has drawn closer in recent days.  So far MASIE September average is 5.0M and SII is 4.7M, with 4 more days remaining in the month. Note 2007 was ~800k km2 in deficit, 2020 ~600k down at day 270, while last year was ~300k below average.

The regional distribution of ice extents is shown in the table below. (Bering and Okhotsk seas are excluded since both are now virtually open water.)

Region	2025270	Day 270 ave.	2025-Ave.	2007270	2025-2007
(0) Northern_Hemisphere	5074777	4798758	276018	4023569	1051207
(1) Beaufort_Sea	483527	520730	-37203	482030	1497
(2) Chukchi_Sea	332213	210352	121861	214	331999
(3) East_Siberian_Sea	499915	280923	218992	311	499604
(4) Laptev_Sea	273431	152794	120636	238340	35091
(5) Kara_Sea	4906	33680	-28774	15113	-10207
(6) Barents_Sea	0	12945	-12945	4851	-4851
(7) Greenland_Sea	165160	225916	-60756	339720	-174560
(8) Baffin_Bay_Gulf_of_St._Lawrence	70284	47480	22804	43624	26660
(9) Canadian_Archipelago	302771	336303	-33533	280360	22410
(10) Hudson_Bay	2415	2252	163	1936	479
(11) Central_Arctic	2938588	2974115	-35527	2615795.38	322792

The table shows large surpluses in Eurasian basins  Laptev, Chukchi and E. Siberian, more than offsetting smaller deficits in Central Arctic, CAA and Greenland seas. Hudson Bay is mostly open water at this time of year. 2025 exceeds the average ice extents by 276k km2, or 6%, and is over 1 wadham greater than 2007 or a surplus of 1.05M km2 of ice extent.

September monthly average ice extent is considered the annual minimum for climate purposes.  Note also that typically the lowest daily value occurs mid September, with a small positive gain between the end of August and end of September.

Why is this important?  All the claims of global climate emergency depend on dangerously higher  temperatures, lower sea ice, and rising sea levels.  The lack of additional warming prior to 2023 El Nino is documented in a post SH Drives UAH Temps Cooler July 2025.

The lack of acceleration in sea levels along coastlines has been discussed also.  See Observed vs. Imagined Sea Levels 2023 Update

Also, a longer term perspective is informative:

Footnote Regarding  SII v.4

NSDIC acknowledged my query regarding the SII (Sea Ice Index) dataset. While awaiting an explanation I investigated further. My last download of the SII Daily Arctic Ice Extents was on July 30, meaning that the most recent data in that file was day 210, July 29. The header on that file was Sea_Ice_Index_Daily_Extent_G02135_v3.

Then on August 1, the downloaded file had the heading Sea_Ice_Index_Daily_Extent_G02135_v4. So it appears that these are now the values from a new version of SII. As I wrote in my query, since March 14 all of the values for Arctic Ice Extents are lower in this new record. The graph above shows the implications for August as an example of estimates from SIIv.4.

In the past, SIIv.3 tracked MASIE with slightly lower values.  But with v.4, larger monthly average deficits to MASIE were reported in July 2025 ( -282k km2) and in August (-440k km2).

The change started in January 2025 and will be the basis for future reporting.  The logic for this is presented in this document: Sea Ice Index Version 4 Analysis

In June 2025, NSIDC was informed that access to data from the Special Sensor Microwave
Imager/Sounder (SSMIS) onboard the Defense Meteorological Satellite Program (DMSP)
satellites would end on July 31 (NSIDC, 2025). To prepare for this, we rapidly developed version
4 of the Sea Ice Index. This new version transitions from using sea ice concentration fields
derived from SSMIS data as input to using fields derived from the Advanced Microwave
Scanning Radiometer 2 (AMSR2) sensor onboard the Global Change Observation Mission – W1
(GCOM-W1) satellite.  On 29 July 2025, we learned that the Defense Department decision to terminate access to DMSP data had been reversed and that data will continue to be available until September 2026.

We are publishing Version 4, however, for these reasons:

• The SSMIS instruments are well past their designed lifespan and a transition to
AMSR2 is inevitable. Unless the sensors fail earlier, the DoD will formally end the
program in September 2026.
• Although access of SSMIS will continue through September 2026, the Fleet
Numerical Meteorology and Oceanography Center (FNMOC), where SSMIS data
from the DMSP satellite are downloaded, made an announcement that “Support
will be on a best effort basis and should be considered data of opportunity.” This
means that SSMIS data will likely contain data gaps.
• We have developer time to make this transition now and may not in the future.
• We are confident that Version 4 data are commensurate in accuracy to those
provided by Version 3.