The arctic ice extents are now reported through end of March 2026, the month whose average is taken as the annual maximum.  As noted previously the wavy polar vortex has hampered ice formation with incusions of warmer southern air into the Arctic circle.  This may be changing according to the most recent image from AER PV blog.

Remarkably, the 2025 annual daily extent maximum of 14.48M km2 was on day 73 of that year.  Arctic ice reached 14.55 on day 63 in 2026, and continued near that level until day 74, before starting the usual decline.

The chart below shows the 20-year averages for Arctic ice extents for March along with 2026, 2025 and 2006 as well as SII v.4.

 

The 20-year average maximum daily ice extent appears at 14.93M km2 on day 71 before starting to decline. MASIE 2006 and 2026 started this period the same and tracked each other until 2026 ended higher by ~200k km2, and slightly above 2025.

The table below shows the distibution of ice extents on day 90 across regions of the Arctic ocean.

Region	2026090	Day 90 Average	2026-Ave.	2006090	2026-2006
(0) Northern_Hemisphere	14149101	14587351	-438250	13913402	235699
(1) Beaufort_Sea	1071070	1070279	791	1068683	2387
(2) Chukchi_Sea	966006	964325	1681	959091	6915
(3) East_Siberian_Sea	1087137	1086309	828	1084627	2510
(4) Laptev_Sea	897845	897135	709	897773	71
(5) Kara_Sea	930404	918948	11456	922164	8240
(6) Barents_Sea	582189	653649	-71460	623912	-41723
(7) Greenland_Sea	569080	667067	-97988	604935	-35856
(8) Baffin_Bay_Gulf_of_St._Lawrence	1403737	1384371	19366	1026934	376804
(9) Canadian_Archipelago	854931	853349	1582	851691	3240
(10) Hudson_Bay	1260887	1255554	5333	1240389	20498
(11) Central_Arctic	3223020	3234756	-11736	3241074	-18054
(12) Bering_Sea	819147	705446	113701	662863	156284
(13) Baltic_Sea	36855	60091	-23235	129348	-92492
(14) Sea_of_Okhotsk	433109	826350	-393242	588167	-155058

The table shows that most regions are close to or above the 20-year average.  The majority of the 3% overall deficit is from Sea of Okhotsk, down ~400k km2,  Smaller deficits are in Barents and Greenland seas, partly offset by a surplus in Bering sea. All of those regions will be nearly ice-free end of summer.

 

 

As for the March Monthly Averages, here is the history:

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring ice and snow extents.

 

The arctic ice extents are now reported through March 16, 2026, an important date just past the annual daily maximum for Arctic ice extents averaged over the last 20 years. As noted in February, the wavy polar vortex has hampered ice formation with incusions of warmer southern air into the Arctic circle.  For example, here is an image from AER PV blog showing temperatures recently:

Remarkably, the 2025 annual daily extent maximum of 14.48M km2 was on day 73 of that year.  Arctic ice reached 14.55 on day 63 in 2026, and continued near that level until yesterday, day 75.

The chart below shows the 20-year averages for Arctic ice extents mid-March along with 2026, 2025 and 2006 as well as SII v.4.

The 20-year average maximum daily ice extent appears at 14.93M km2 on day 71 before starting to decline. MASIE 2006 and 2026 started this period the same and ended the same at 14.42M km2. 2025 started much lowered but matched the other two years on day 75.  SII v.4 continues to show lower extents than MASIE,  a deficit on the order of  220k km2 during March and on day 75.

The table below shows the distibution of ice extents on day 75 across regions of the Arctic ocean.

Region	2026075	Average Day 75	2026-Ave.	2006075	2026-2006
(0) Northern_Hemisphere	14413747	14882167	-468421	14420679	-6932
(1) Beaufort_Sea	1071070	1070384	686	1069711	1359
(2) Chukchi_Sea	966006	965902	104	964227	1779
(3) East_Siberian_Sea	1087137	1087113	24	1086702	435
(4) Laptev_Sea	897845	897838	7	897773	71
(5) Kara_Sea	933375	921644	11731	921428	11947
(6) Barents_Sea	616802	640512	-23710	646196	-29394
(7) Greenland_Sea	585405	633630	-48225	613161	-27756
(8) Baffin_Bay_Gulf_of_St._Lawrence	1400707	1511237	-110530	1134817	265890
(9) Canadian_Archipelago	854931	853379	1551	852715	2215
(10) Hudson_Bay	1260887	1258334	2553	1251360	9527
(11) Central_Arctic	3206408	3223651	-17243	3244243	-37835
(12) Bering_Sea	901252	729963	171289	635252	266000
(13) Baltic_Sea	89899	77762	12138	175063	-85164
(14) Sea_of_Okhotsk	522126	992634	-470508	874372	-352247

The table shows that most regions are close to or above the 20-year average.  Two major deficits are in Baffin Bay and Sea of Okhotsk, partly offset by a smaller surplus in Bering sea. The overall 2026 MASIE deficit is 3% of the 20-year average.

 

 

 

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring ice and snow extents.

 

The arctic ice extents are now reported through February 2026, early on showing rising refreezing rates bringing Arctic ice extents within 200k km2 of the 20-year average.  In the last 2 weeks the wavy Polar Vortex pushed cold south and replaced it with warmer southern air.   Remarkably, Arctic ice reached 14.44 on day 43 in 2026, virtually matching the 2025 annual daily extent maximum of 14.48M km2 on day 80 of that year.

The chart below shows the 20-year averages for Arctic ice extents mid-Febrauary along with 2026 and 2025, as well as SII v.4.

As stated previously, likely due to a wavy polar vortex, MASIE 2026 grew rapidly in February reaching 14.52 M km2 on day 51, surpassing the 2025 max of 14.48 on day 80.  In the last week the extent dropped back down to 14.4 M. Sea Ice Index (SII v4) reported lower extents than MASIE in February, averaging -250k km2 on a daily basis.

The vortex temperature shifts are shown below in charts from AER AO/PV blog.

The table below shows the distibution of ice extents on day 59 across regions of the Arctic ocean.

Region	2026059	Day 59 Average	2026-Ave.	2025059	2026-2025
(0) Northern_Hemisphere	14384094	14861155	-477061	14000679	383416
(1) Beaufort_Sea	1071070	1070420	650	1071001	69
(2) Chukchi_Sea	966006	965473	533	965989	17
(3) East_Siberian_Sea	1087137	1087111	27	1087137	0
(4) Laptev_Sea	897845	897837	8	897845	0
(5) Kara_Sea	914161	922224	-8062	925512	-11351
(6) Barents_Sea	567312	604234	-36922	361405	205907
(7) Greenland_Sea	731619	627908	103711	637961	93658
(8) Baffin_Bay_Gulf_of_St._Lawrence	1264992	1512995	-248004	1357658	-92666
(9) Canadian_Archipelago	854931	853573	1358	854878	53
(10) Hudson_Bay	1260870	1260493	377	1260903	-33
(11) Central_Arctic	3145110	3209967	-64857	3159772	-14663
(12) Bering_Sea	724115	659010	65105	577908	146207
(13) Baltic_Sea	136175	92656	43518	40575	95599
(14) Sea_of_Okhotsk	737815	1057674	-319858	774415	-36599

The table shows that most regions are close to or above the 20-year average.  Two major deficits are in Baffin Bay and Sea of Okhotsk, partly offset by several smaller surpluses, mostly in Greenland Sea, Baltic and Bering seas. The overall 2026 MASIE deficit is 3% of the 20-year average.

 

 

 

 

The arctic ice extents are now reported through mid-February 2026, showing rising refreezing rates bringing Arctic ice extents within 200k km2 of the 20-year average.  Remarkably, the last two days virtually matched the 2025 annual extent maximum of 14.48M km2 on day 80 of that year, compared to 14.44 on day 43 in 2026.

The chart below shows the 20-year averages for Arctic ice extents mid-Febrauary along with 2026 and 2025, as well as SII v.4.

As stated previously, likely due to a wavy polar vortex, MASIE 2026  refroze slowly in January reaching a deficit of 622k km2 on day 26.  Since then ice grew at a higher rate, ending this period 176k km2 below average, or 1% down. Note that compared to day 44 last year, 2026 ice is more than half a Wadham greater, 656k km2.  And as mentioned above, 2025 will not match yesterday until day 80. Note SII v.4 tracks lower than MASIE throughout, on average in deficit by 242K km2.

Region	2026044	Average day 44	2026-Ave.	2025044	2026-2025
(0) Northern_Hemisphere	14427481	14603337	-175856	13771518.64	655962
(1) Beaufort_Sea	1071070	1070384	686	1071000.73	69
(2) Chukchi_Sea	966006	965785	222	965989.12	17
(3) East_Siberian_Sea	1087137	1087132	5	1087137.23	0
(4) Laptev_Sea	897845	897838	7	897844.8	0
(5) Kara_Sea	935023	909437	25586	911762.37	23261
(6) Barents_Sea	649606	566421	83185	434920.5	214686
(7) Greenland_Sea	772110	625671	146439	635758.41	136351
(8) Baffin_Bay_Gulf_of_St._Lawrence	1040295	1429059	-388764	1335264.28	-294969
(9) Canadian_Archipelago	854931	853531	1399	854877.96	53
(10) Hudson_Bay	1260870	1260595	276	1260903.34	-33
(11) Central_Arctic	3235930	3204874	31056	3195022.33	40907
(12) Bering_Sea	689769	671512	18256	333643.58	356125
(13) Baltic_Sea	155657	88990	66666	35593.84	120063
(14) Sea_of_Okhotsk	742439	914421	-171982	720462	21977

The table shows that most regions are close to or above the 20-year average.  Two major deficits are in Baffin Bay and Sea of Okhotsk, partly offset by several smaller surpluses, mostly in Greenland Sea, Barents and Bering seas.

 

 

 

 

The arctic ice extents are now fully reported for January 2026, showing refreezing rates fluctuating, likely due to a wavy polar vortex sending cold Arctic air to sub-arctic latitudes and replacing it with warmer southern air.

From AER Polar Vortex blog:

As seen in Figure iii (and also Figure 12) the PV has an elongated shape in appearance for much of the next two weeks in contrast to the more circular PV of early January. The PV has a “split” appearance this week and into next week, a character trait or signature of a more extreme stretched PV. I think the more extreme nature of the stretched PV is consistent with the model forecasts of extreme cold in the US and even potential snowstorms. But then at least in this animation there is a clear PV split with two distinct and independent PV centers.

Figure iii. Forecasted average 10 mb geopotential heights (dam; contours) and geopotential height anomalies (m; shading) across the Northern Hemisphere for 19 Jan 2026 and forecasted from 20 Jan 2026 to 03 Feb 2026. The forecasts are from the 00Z 19 Jan 2026 GFS model ensemble.

The chart below shows the 20-year averages for Arctic ice extents in January along with 2026 and 2025, as well as SII v.4.

Note MASIE 2025 started 5 to 600k km2 (or half a Wadham) below the 20 year average, but by day 12 cut the deficit to 151k km2, or a gap of 1%. Freezing rate went flat for a week before recovering and ending the month nearly 14M km2, 365k id deficit or 3%.  SII v.4 tracked lower than MASIE throughout January, averaging ~200k km2 lower for the month. The chart below shows the distribution of ice extent across the Arctic regions at January 31, 2026.

Region	2026031	Average Day 31	2026-Ave.	2025031	2026-2025
(0) Northern_Hemisphere	13954044	14319064	-365020	13543739.54	410305
(1) Beaufort_Sea	1071070	1070419	651	1071000.73	69
(2) Chukchi_Sea	966006	965975	31	965989.12	17
(3) East_Siberian_Sea	1087137	1087067	70	1087137.23	0
(4) Laptev_Sea	897845	897825	20	897844.8	0
(5) Kara_Sea	923456	917599	5857	921519.96	1936
(6) Barents_Sea	582372	556751	25621	428814.24	153558
(7) Greenland_Sea	663996	613445	50551	614788.59	49207
(8) Baffin_Bay_Gulf_of_St._Lawrence	1027979	1315356	-287378	1080930.32	-52952
(9) Canadian_Archipelago	854931	853582	1349	854877.96	53
(10) Hudson_Bay	1260870	1260784	86	1260903.34	-33
(11) Central_Arctic	3202511	3210553	-8042	3211378.6	-8867
(12) Bering_Sea	670583	642788	27795	534452.21	136131
(13) Baltic_Sea	114996	61637	53359	39333.65	75663
(14) Sea_of_Okhotsk	549996	809973	-259977	559692	-9696

The table shows that most regions are close to the 20-year average.  Two major deficits are in Baffin Bay and Sea of Okhotsk, partly offset by several smaller surpluses.

 

 

 

The Arctic ice extents are now fully reported for 2025, ending the year below average despite a higher rate of growth through December.

Note MASIE 2025 started 1M km2 (or 1 Wadham) below the 19 year average, but cut the deficit to 428k km2, or a gap of 3%. SII v.4 tracked lower than MASIE during December, drawing closer the last week. The chart below shows the distribution of ice extent across the Arctic regions at yearend 2025.

Region	2025365	Day 365 Average	2025-Ave.	2024365	2025-2024
(0) Northern_Hemisphere	12611676	13039302	-427626	12435177	176499
(1) Beaufort_Sea	1071070	1070458	612	1071001	69
(2) Chukchi_Sea	966006	964771	1235	965989	17
(3) East_Siberian_Sea	1087137	1087133	4	1087137	0
(4) Laptev_Sea	897845	897841	4	897845	0
(5) Kara_Sea	867623	887208	-19585	876527	-8904
(6) Barents_Sea	254882	423978	-169096	345715	-90832
(7) Greenland_Sea	668550	595658	72891	574537	94013
(8) Baffin_Bay_Gulf_of_St._Lawrence	768306	982649	-214343	982716	-214409
(9) Canadian_Archipelago	854931	853618	1313	854878	53
(10) Hudson_Bay	1256284	1215695	40589	922416	333868
(11) Central_Arctic	3174354	3206560	-32206	3207164.49	-32811
(12) Bering_Sea	350519	403002	-52483	325489.93	25029
(13) Baltic_Sea	14031	31873	-17843	15271.77	-1241
(14) Sea_of_Okhotsk	366812	393742	-26929	302941	63871

The major deficits are in Barents Sea and Baffin Bay (Atlantic basins), along with smaller losses in Bering and Okhotsk (Pacific basins).

Background from Previous Post Updated to Year-End 2025

Some years ago reading a thread on global warming at WUWT, I was struck by one person’s comment: “I’m an actuary with limited knowledge of climate metrics, but it seems to me if you want to understand temperature changes, you should analyze the changes, not the temperatures.” That rang bells for me, and I applied that insight in a series of Temperature Trend Analysis studies of surface station temperature records. Those posts are available under this heading. Climate Compilation Part I Temperatures

This post seeks to understand Arctic Sea Ice fluctuations using a similar approach: Focusing on the rates of extent changes rather than the usual study of the ice extents themselves. Fortunately, Sea Ice Index (SII) from NOAA provides a suitable dataset for this project. As many know, SII relies on satellite passive microwave sensors to produce charts of Arctic Ice extents with complete coverages going back to 1989.  Version 3 was more closely aligned than Version 4 with MASIE, the modern form of Naval ice charting in support of Arctic navigation. The SII User Guide is here.

There are statistical analyses available, and the one of interest (table below) is called Sea Ice Index Rates of Change (here). As indicated by the title, this spreadsheet consists not of monthly extents, but changes of extents from the previous month. Specifically, a monthly value is calculated by subtracting the average of the last five days of the previous month from this month’s average of final five days. So the value presents the amount of ice gained or lost during the present month.

These monthly rates of change have been compiled into a baseline for the period 1980 to 2010, which shows the fluctuations of Arctic ice extents over the course of a calendar year. Below is a graph of those averages of monthly changes up to and including this year. Those familiar with Arctic Ice studies will not be surprised at the sine wave form. December end is a relatively neutral point in the cycle, midway between the September Minimum and March Maximum.

The graph makes evident the six spring/summer months of melting and the six autumn/winter months of freezing.  Note that June-August produce the bulk of losses, while October-December show the bulk of gains. Also the peak and valley months of March and September show very little change in extent from beginning to end.

The table of monthly data reveals the variability of ice extents over the last 4 decades, with gains in blue cells and losses in red cells.

The values in January show changes from the end of the previous December, and by summing twelve consecutive months we can calculate an annual rate of change for the years 1980 to 2025.

As many know, there has been a decline of Arctic ice extent over these 40 years, averaging 70k km2 per year. But year over year, the changes shift constantly between gains and losses, ranging up to +/- 500k km2, (2024 being exceptional). Since 1989 the average yearend gain/loss is nearly zero, -0.049k km2 to be exact.

Moreover, it seems random as to which months are determinative for a given year. For example, much ado was printed about 2023 losing more ice than usual June through September. But then the final 3 months of 2023 more than made up for those summer losses, resulting in a sizeable gain for the year.

As it happens in this dataset, October has the highest rate of adding ice. The table below shows the variety of monthly rates in the record as anomalies from the 1980-2010 baseline. In this exhibit a red cell is a negative anomaly (less than baseline for that month) and blue is positive (higher than baseline).

Note that the  +/ –  rate anomalies are distributed all across the grid, sequences of different months in different years, with gains and losses offsetting one another.  As noted earlier,  in 2023 the outlier negative months were June through September where unusual amounts of ice were lost.  Then unusally strong gains in October to December resulted in a large annual gain, compared to the baseline. The bottom line presents the average anomalies for each month over the period 1979-2025.  Note the rates of gains and losses mostly offset, and the average of all months in the bottom right cell is virtually zero.

A final observation: The graph below shows the Yearend Arctic Ice Extents for the last 35 years.

Year-end Arctic ice extents (last 5 days of December) show three distinct regimes: 1989-1998, 1998-2010, 2010-2025. The average year-end extent 1989-2010 is 13.4M km2. In the last decade, 2011 was 13.0M km2, and six years later, 2017 was 12.3M km2. 2021 rose back to 13.0  2024 slipped back to 12.2M, and 2025 is back up to 12.4M. So for all the the fluctuations, the net is virually zero, or a loss of one tenth of a Wadham (0.1M) from 2010. Talk of an Arctic ice death spiral is fanciful.

These data show a noisy, highly variable natural phenomenon. Clearly, unpredictable factors are in play, principally water structure and circulation, atmospheric circulation regimes, and also incursions and storms. And in the longer view, today’s extents are not unusual.

 

 

 

 

 

The polar vortex is pronounced this year, resulting in warmer temperature over the Arctic ocean, and slowing the normal sea ice recovery.  Dr. Judah Cohen at AER Arctic Oscillation blog provides information like the chart above.

After a pattern of solidly growing sea ice extent in October, a slowdown occurred in November, coincidental with the warm spots shown above.  The graph below shows 2025 compared to the 19 year average (2006 to 2024 inclusive), to SII (Sea Ice Index) and some notable years.

According to MASIE. the average November adds ~2.5M km2 of sea ice extent, which is matched also by 2007.  2024 started below average, but gained steadily to close the gap.  2025 started at the same level, but the refreezing slowed down, ending November in deficit by 1.1M km2.  SII shows even lower ice extents (the last two days not yet reported.)

The table below shows the distribution of ice in the Arctic Ocean basins, suggesting two places where ice recovery is lagging.

Region	2025334	Day 334 Ave.	2025-Ave.	2007334	2025-2007
(0) Northern_Hemisphere	9784037	10880420	-1096383	11009948	-1225911
(1) Beaufort_Sea	1071070	1069623	1447	1058872	12198
(2) Chukchi_Sea	879082	791207	87875	687829	191253
(3) East_Siberian_Sea	1087137	1083943	3194	1082015	5122
(4) Laptev_Sea	897845	897824	21	897613	232
(5) Kara_Sea	565299	792107	-226808	826319	-261020
(6) Barents_Sea	28050	242740	-214690	216525	-188474
(7) Greenland_Sea	550413	539687	10726	618844	-68431
(8) Baffin_Bay_Gulf_of_St._Lawrence	412284	664437	-252153	708497	-296212
(9) Canadian_Archipelago	854931	853431	1500	850249	4682
(10) Hudson_Bay	188797	543322	-354525	751382	-562585
(11) Central_Arctic	3037637	3193296	-155659	3183072.72	-145436
(12) Bering_Sea	145331	138776	6555	72644.62	72687
(13) Baltic_Sea	4226	4452	-225	0	4226
(14) Sea_of_Okhotsk	58288	61277	-2989	53052	5236

Overall ice extent was 1.1M km2 below average or 10%.  About half the deficit comes from the European Atlantic basins, Kara and Barents seas.  The other half is mostly from N. America’s Hudson and Baffin bays. Ice in these regions operate on the LIFO principle, last in and first out.

At this point in the year, Arctic ice has grown back to 65% of last March maximum with 2.5 months to catch up.   AER  suggests that things may shift again in December:

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring ice and snow extents.

 

 

The animation shows the rapid growth of Arctic ice extent during October 2025, from day 274 to day 304, yesterday.  For all of the fuss over the September minimum, little is said about Arctic ice growing 3M km2, that’s 3 Wadhams in one month!.  Look on the left (Russian side) at the complete closing of the Northern Sea Route for shipping.

The graph below shows 2025 compared to the 19 year average (2006 to 2024 inclusive), to SII (Sea Ice Index) and some notable years.

This year October added 2.6M km2 from end of September compared to an average October increase of 3.4M km2.  The first two weeks were above average, before the refreezing rate slowed down ending in a deficit of ~0.5M km2.  In other terms the end of October ice extents were four days behind the average, according to MASIE.  SII started the same, but tracked lower in the second half of October.

The table below shows the distribution of ice in the Arctic Ocean basins.

Region	2025304	Day 304 Ave.	2025-Ave.	2007304	2025-2007
(0) Northern_Hemisphere	7867621	8401977	-534356	8175072	-307451
(1) Beaufort_Sea	975681	937777	37904	1038126	-62444
(2) Chukchi_Sea	683493	466318	217175	242685	440809
(3) East_Siberian_Sea	1087032	952325	134707	835071	251961
(4) Laptev_Sea	849204	848501	703	887789	-38585
(5) Kara_Sea	137515	478870	-341355	311960	-174445
(6) Barents_Sea	1466	81088	-79621	52823	-51356
(7) Greenland_Sea	351374	418343	-66969	443559	-92184
(8) Baffin_Bay_Gulf_of_St._Lawrence	128777	247258	-118481	289374	-160596
(9) Canadian_Archipelago	568663	740190	-171526	817220	-248557
(10) Hudson_Bay	8609	66501	-57892	48845	-40236
(11) Central_Arctic	3051977	3153485	-101508	3206345.33	-154368

Overall ice extent was 534k km2 below average or 6%.  Surpluses appear on the Eurasian shelf seas of Beaufort, Chukchi and East Siberian, while sizeable deficits are shown elsewhere on the Atlantic side, especially Kara, Baffin Bay, Canadian Archipelago and Central Arctic.

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring ice and snow extents.