• by Sarah Mahoney  @mahoney_sarah, December 22, 2009

In a move that shows just how hard retailers are working this season, both J.C. Penney and Best Buy are using the holiday season's 11th hour not just to pitch last-minute gift ideas, but to plug after-Christmas sales.

Penney says it will open its doors at 5 a.m. on Dec. 26 -- the earliest in its history -- offering more than 100 doorbusters and 99-cent shipping on JCP.com. Sales circulars will feature "instant money" coupons for use in-store or online, shaving $10 off a $50 purchase. And because Dec. 26 is traditionally the biggest teen shopping day of the year as kids race to the mall to spend gift money, the Plano, Texas-based chain plans to offer plenty of specials on such brands as Arizona, Decree, Levi's, Vans and Nike.

Best Buy is already hyping its post-holiday computer deals, and will kick off a two-day sale on Dec. 25, with markdowns on netbooks, laptops, desktops, and service bundles. For example, Lenovo 10.1" netbooks will go for just $197 (they had been priced at $300). And a Dell Studio 17" notebook will sell for $700 (down from $780).

The moves come as retailers continue to struggle with standoffish shoppers. And getting walloped by last weekend's snowstorm didn't help. The International Council of Shopping Centers says that in the latest week, ending Dec. 19, its sales index gained just 0.6% from last year.

The storm turned "Super Saturday" -- the Saturday before Christmas which in many years has been the highest sales volume day of the year -- "into a super disappointment for retailers," Michael Niemira, ICSC director of research and chief economist, says in a statement. "The good news is that there was some offsetting of that weakness with advance sales on Friday ahead of the storm and even Saturday morning in the New York area.

"Additionally, consumers' average holiday-gift completion rate rose to only 70.9% through Sunday, which was almost 10 percentage points behind the same point last year (80.1%) -- and that statistic suggests that the catch-up will be intense as consumers complete their holiday gift-buying this week."