Fewer shoppers and sales in stores this holiday season

People get an early start on Black Friday shopping deals at a Walmart Superstore on November 22, 2012 in Rosemead, California, as many retailers stayed opened during the Thanksgiving celebrations, evidence that even this cherished American family holiday is falling prey to the forces of commerce. AFP PHOTO / Frederic J. BROWN (Photo credit should read FREDERIC J. BROWN/AFP/Getty Images)

Some 21.2 percent fewer shoppers trudged through brick-and-mortar stores last week compared with the same week a year ago, according to data firm ShopperTrak. In-store sales dropped by 3.1 percent to $42.7 billion.

It’s the third consecutive week of lower sales. Friday through Sunday were expected to be the four busiest holiday shopping days after Black Friday this year.

Winter weather dissuaded many shoppers in the Midwest from heading out to the malls.

And Black Friday discounts starting before Thanksgiving weekend nationwide may have inspired some shoppers to cross items off their lists earlier in the year.

“November is continuing to gain a larger percentage of the split of holiday sales,” ShopperTrak founder Bill Martin said. In-store sales were up 3.4 percent for the month of November, according to ShopperTrak.

Meanwhile, online shopping continues to grow. Some 23 percent more shoppers visited online stores between Dec. 15 and Dec. 18 compared with a year ago, according to Custora Pulse, a retail data tracker. Sales rose 13 percent.

Holiday sales can make or break a retailer, since stores can bring in 40 percent of their annual revenue between Nov. 1 and Dec. 31.