The effect won’t be as bad as last year’s pre-Christmas snowstorm that similarly paralyzed parts of the East Coast. That cost retailers an estimated $2 billion, according to weather research firm Planalytics.

About $10 billion in retail sales usually occurs Dec. 26-27, ShopperTrak says. Bad weather likely delayed about 10 percent of that.

The storm’s effects weren’t enough to change ShopperTrak’s estimate for a 4 percent gain over last year in revenue for the Nov. 1-Dec. 31 holiday season. Retailers will still see much of the spending when shoppers return to stores as streets are cleared and transportation restored.

This year’s storm cost retailers 11.2 percent of their foot traffic Sunday and 13.9 percent Monday, ShopperTrak estimates.

The fact that the day after Christmas fell on a Sunday this year might have hurt sales a bit even where it didn’t snow, ShopperTrak founder Bill Martin said, because of local laws that limit or ban Sunday hours in some places.

Dec. 26 will rank 10th-busiest day of the holiday shopping season, the firm estimates. Last year, it was second-busiest behind Black Friday.

Black Friday was again the busiest shopping day this year, with $10.69 billion in sales. Coming in second was Dec. 23, as last-minute shoppers picked up $7.86 billion in gifts and other items and gave retailers a strong finish.

Strong sales the week ending Dec. 31, which accounts for about 15 percent of total holiday spending, could make this year the best holiday season ever.

Earlier this week, MasterCard Advisors SpendingPulse, another research firm, said consumer spending excluding autos rose 5.5 percent to $584.3 billion from Nov. 5 through Dec. 24, compared with the same period a year ago. SpendingPulse tracks all forms of spending, including cash.

The total beat the 2007 record of $566.3 billion for the period, though adjusted for inflation, it is slightly below the record.