The holiday season is off to a bumpy start for online retailers, raising the suspense as final deadlines loom for Christmas shipping.

To date, holiday sales are up a middling 3 percent, with sales for the week ended Dec. 6 having reached $4.6 billion, according to comScore.

That’s heavier than any week during last year’s disastrous holiday season, but still short of weekly records seen in 2007, the e-commerce research firm said.

While Internet sales on Black Friday rose 11 percent and sales on Cyber Monday rose 5 percent to $887 million, this past weekend was a clunker, with sales actually dropping from year-ago levels.

“Hopefully… the weekend softness was just a temporary hiccup,” comScore Chairman Gian Fulgoni said.