The lowest ice extent in the Arctic Ocean this year occurred on September 11, but ice extent can vary greatly from day to day due to local conditions of weather and ocean current. A better measure of trends is the average ice extent for all of September, compared to all the other Septembers for which we have satellite data. Summer Arctic Ocean ice cover is about 60% what it was 35 years ago.

http://nsidc.org/arcticseaicenews/files/2015/10/monthly_ice_09_NH-350×270.png

The Arctic melt season has ended and sea ice extent is now increasing after reaching the fourth lowest minimum on record, on September 11.
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Through 2015, the linear rate of decline for September Arctic ice extent over the satellite record is 13.4% per decade, relative to the 1981 to 2010 average. The nine lowest September ice extents over the satellite record have all occurred in the last nine years.

http://nsidc.org/arcticseaicenews/files/2015/10/n_extn_hires-350×417.png

(National Snow and Ice Datacenter)