Yes, the NSIDC chart does a 5 day running average, as has pointed out on occasion.
The Actual daily values for 2017 NSIDC SIE are; 2012 values. July 3rd is day 185
x 106 km2
2017, 07, 01, 9.244 2012, 06, 30, 9.335
2017, 07, 02, 9.154 2012, 07, 01, 9.062
2017, 07, 03, 9.087 2012, 07, 02, 8.971
2017, 07, 04, 8.963 2012, 07, 03, 8.954