People looking to work off the Thanksgiving dinner can head out into the early-morning cold tomorrow to lighten their wallets at the region’s stores.

Retailers are once again trying to spur consumers into spending money during the holiday season by opening stores’ doors when most people are in the middle of a good night’s sleep

For example:

•JCPenney stores in some locations will open at 4 a.m.

•Circuit City stores open at 5 a.m.

•Bob’s, A.J. Wright and Macy’s stores at 6 a.m.

•BJ’s Wholesale Clubs at 7 a.m.

But some stores at Wrentham Village Premium Outlets in Massachusetts will once again beat most of their competitors out of the gate, opening at 12:01 a.m.

Retailers go to such lengths for a simple reason — cold cash.

“MasterCard data shows that for retailers in the top gift-buying categories, Black Friday is indeed the biggest day of the season, and people know to get out of bed early to cash in on the myriad of bargains that are offered in the wee hours of the morning,” said Larry Flanagan, chief marketing officer of MasterCard Worldwide. “In fact, for electronics and appliance stores, nearly half of their purchase volume occurs before 10 a.m., with the early hour from 7 a.m. to 8 a.m. being the busiest.”

The day after Thanksgiving has long been known as Black Friday in the retailing business because it’s one of the busiest shopping days of the year. The day generally produces sales that push stores into profitability for the year.

The term became something of a misnomer in the 1990s, as the nation’s peak shopping day slipped closer to Christmas in some years.

Last year, though, Black Friday was the busiest holiday shopping day.

“This holiday season needs all the help it can get — shoppers have been off to a slow start this year, but retailers can rest assured that shoppers will be waiting when the doors open on Friday,” said Tod Marks, senior editor of Consumer Reports magazine.

Nearly one-quarter of the people surveyed by Consumer Reports researchers said they would shop tomorrow, up from the 20 percent who said they shopped the day last year.

“Consumers are expected to wait for those early-morning openings and take advantage of special sales,” according to Consumer Reports. Fourteen percent of survey respondents said they queued up in an early-morning line last year to grab a door-buster bargain.

Nearly 59 million Americans shopped last year on the Friday after Thanksgiving, according to the National Retail Federation, a trade group. One-quarter of those were die-hards who showed up at a store by 5 a.m.The push to grab consumers intent on keeping their holiday spending in line gets an earlier start this Thanksgiving than even the bleary-eyed madness provoked by the midnight store openings that swept across the country last year.

Some retailers are offering sales breaks today that they typically reserve for tomorrow. Last year, nearly 9.8 million people shopped on Thanksgiving Day, according to the National Retail Federation.

Some Kmart stores will open from 7 a.m. to 9 p.m. on Thanksgiving, although not the ones in Cranston or South Attleboro.

Wal-Mart will move some Black Friday promotions to its Web site Thanksgiving Day.

Retailers go to these lengths because sales between Thanksgiving and Christmas can represent anywhere from 25 to 40 percent of their annual sales. Last year however, holiday sales represented only 19.6 percent of total retail sales.

This year, the retail federation is predicting that sales will rise 4 percent to $474.5 billion.

“Retailers are in for a somewhat challenging holiday season as consumers are faced with numerous economic obstacles,” said NRF chief economist Rosalind Wells. “With the weak housing market and current credit crunch, consumers will be forced to be more prudent with their holiday spending.”

pgrimald@projo.com