Four days after the flakes started flying in the blizzard of 2013, nearly 40,000 customers in Massachusetts were still without power Tuesday morning. 

National Grid had 10,016 customers without electricity as of 10 a.m. Tuesday, with the bulk of those outages in Plymouth County.

The utility had previously predicted that the lights in all Massachusetts households in its service territory would be back on by midnight Tuesday, but its website on Tuesday said the conditions in Plymouth County, where 8,900 customers were still in the dark, were still being assessed.

Meanwhile, NStar reported 29,618 customers still without power as of 8 a.m. on Tuesday with some parts of the South Shore and upper Cape not expected to get electricity back until Thursday.