The sea-ice extent on 10 September stood at 4.14 million sq km, some way short of the 3.39 million sq km record low in 2012.
Arctic sea-ice cover grows each autumn and winter, and shrinks each spring and summer.
It has long been regarded as a sensitive indicator of change to the Earth's climatic system.
The ice extent has been tracked by the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado, using satellite measurements.
However, the centre cautioned that the figures were preliminary, adding that changing winds could still push the ice extent lower.