The red trend line for 2015 is clearly levelling off during the second half of February, coinciding with the observed stall in extent/area growth (see this previous blog post on a possible record low and early maximum). The 2015 trend line shows the same behaviour as that of last year, when a decreased growth rate at the end of the freezing season had the maximum volume - reached somewhere in April, because ice keeps thickening a while longer even though melting has started at the fringes of the ice pack - back to the level of previous years, negating the volume rebound of the 2013 melting season.
This month data has been updated all the way up to March 8th, instead of just the end of February. The extra data might be preliminary, but here goes:
This year's volume obviously hasn't come any closer to that of last year. In fact, the gap has widened from 1291 to 1562 km3. But other than that 2015 has come closer to all other years in the 2006-2015 record. The gap with 2013, for instance, has narrowed from 2496 to 1307 km3, almost 50%. 2015 is now almost on a par with 2010, the year of the big volume crash in spring (gap was 1007 km3 at the end of January, 137 km3 now).
The PIOMAS volume graph produced by Wipneus shows the details more clearly: