The monthly average for March represents the annual maximum for Arctic ice extent.  The graph shows the 12-year March average in MASIE is 15M km2, with SII about 200k km2 less.  In this period six years were higher and seven lower, including a virtual tie between 2019, 2015 and 2007, slightly higher than 2017 and 2018.  In either MASIE or SII this March is ~330k km2 or 2% below the 12-year average.

As we will see, March 2019 ended with a flash melt that reduced extents dramatically in the final week or so.  First the graph of March comparing the daily extents.

Note that 2019 was close to average as recently as day 79 before dropping well below average and recent years.  As reported previously, most of the decline was due to early melting in Bering Sea, which loses its ice every Spring anyway. Below compares NH ice extents with and without Bering ice.

The gap between the black and green lines shows Bering contributed on average ~600k km2 to overall NH ice extents at the beginning of February, increasing to 800k km2 by end of March.  In 2019, the gap between the cyan and purple lines shows ~500k km2 of Bering Ice starting in February, decreasing to 140k km2 by March, then increasing up to 450k km2, and now back down to 180k km2. When the Bering volatility is set aside, the purple and green lines show Arctic ice excluding Bering was above average most of the month, and only slightly lower at the end.

So what has been happening?  In two words: Polar Vortex.  When cold Arctic air descends into parts of North America and Euarasia, warm moist air intrudes into the Arctic to replace it, and ice extents are reduced. For example, see the recently reported balmy weather in UK, and soon to be switched to bitter cold weather. From the Express  UK weather forecast: SHOCK Map shows Britain ENGULFED by freezing Arctic weather front

The cold front is shown in the image, The link underneath goes to the video.

//players.brightcove.net/2540076170001/B1Hli6KCG_default/index.html?videoId=6020946025001#t=12s

The table below shows extents for day 90 comparing 2019 to the 12 year average, and also showing the 600k km2 loss of ice in just 8 days at month end.

Region	2019090	Day 090  Average	2019-Ave.	2019082	2019090-2019082
(0) Northern_Hemisphere	13983435	14786570	-803135	14600645	-617210
(1) Beaufort_Sea	1070498	1070149	348	1070291	207
(2) Chukchi_Sea	945075	965775	-20700	966006	-20931
(3) East_Siberian_Sea	1087137	1086034	1103	1087137	0
(4) Laptev_Sea	897845	896685	1160	897845	0
(5) Kara_Sea	892123	917893	-25770	926462	-34340
(6) Barents_Sea	515799	658886	-143086	681050	-165251
(7) Greenland_Sea	585051	659518	-74467	552178	32873
(8) Baffin_Bay_Gulf_of_St._Lawrence	1343734	1456673	-112939	1431122	-87388
(9) Canadian_Archipelago	853337	852817	520	853337	0
(10) Hudson_Bay	1260903	1253798	7105	1260903	0
(11) Central_Arctic	3238381	3233007	5374	3227734	10647
(12) Bering_Sea	178917	803209	-624292	446151	-267235
(13) Baltic_Sea	25134	68136	-43002	41886	-16752
(14) Sea_of_Okhotsk	1086939	851929	235010	1150521	-63582

Note that BCE (Beaufort, Chukchi and East Siberian) is rock solid, along with Laptev.  Atlantic melting has begun, with the largest losses in Barents and Baffin Bay.  The major deficit in Bering is there, And while Okhotsk has started melting, it remains 235k km2 above average at this time.