I fully agree with Nightvid, but, just for grins, I correlated a normalized version of average winter sea ice extent with average summer sea ice extent. The correlation is reasonably strong, but negative.

The raw data is NSIDC extent data from 1979 through 2014. For each day (leap year's ignored), I computed the standard deviation for that day. For each day, I took (extent minus mean) divided by standard deviation. This more-or-less removes the seasonal wave from the data. I then computed the average deviation for each year, and subtracted that from each day's deviation. This more-or-less adjusts for the fact that it's getting warmer from year to year.

I then plotted, for each year, the average normalized winter value (1/1 through 3/31), with the average normalized late summer value (8/1 through 10/31). 2012 is the bottom-right dot. 1996 and 2006 are the upper-left dots.

This suggests that when winter sea ice is extent is large, summer extent will be small. And vice versa. 2015 currently looks a lot like 2006, and both those years look a lot like 1996, but slid down on the graph.