NSIDC Daily Extent:
2012 was a leap year, now comparing same Julian days.
2012, 07, 14, 7.868..............2015, 07, 15, 8.615, -131k.....+747k
2012, 07, 15, 7.705, -163k....2015, 07, 16, 8.403, -212k
2012, 07, 16, 7.606, -99k.....2015, 07, 17, 8.271, -132k
2012, 07, 17, 7.481, -125k....2015, 07, 18, 8.120, -151k
2012, 07, 18, 7.420, -61k.....2015, 07, 19, 7.932, -188k
2012, 07, 19, 7.350, -70k.....2015, 07, 20, 7.903, - 29k
2012, 07, 20, 7.340, -10k.....2015, 07, 21, 7.807, - 96k
2012, 07, 21, 7.297, -113k....2015, 07, 22, 7.658, -149k.....+361k
2012, 07, 22, 7.184, -113k....2015, 07, 23, 7.548, -110k.....+364k
2012, 07, 23, 7.118, -66k.....2015, 07, 24, 7.434, -114k.....+316k
2012, 07, 24, 7.035, -83k.....2015, 07, 25, 7.320, -114k.....+285k
2012, 07, 25, 6.931, -104k....2015, 07, 26, 7.335, + 15.......+404k
2012, 07, 26, 6.809, -122k....2015, 07, 27, 7.236, - 99.......+427k
2012, 07, 27, 6.677, -132k
2012, 07, 28, 6.600, -77k
2012, 07, 29, 6.478, -122k
2012, 07, 30, 6.400, -78k
2012, 07, 31, 6.368, -32k
Verg