• by Sarah Mahoney  @mahoney_sarah, October 6, 2010

The National Retail Federation is predicting that retail sales will climb 2.3% this holiday season, coming in at $447.1 billion. And while that's a snowflake or two below the 2.5% annual average over the last 10 years, it's a welcome prediction for retailers, still smarting from the last two seasons.

The International Council of Shopping Centers released an even more upbeat forecast, calling for an increase of between 3% and 3.5%, the largest increase since 2006.

While the holiday period is always a bit of a showdown between shoppers holding out for markdowns and retailers reluctant to cut prices, experts say stores are likely to pull the promotional trigger much faster this season. And consumer confidence is low, as fears about the strength of the recovery persist. "Retailers are expected to compensate for this fundamental shift in shopper mentality by offering significant promotions throughout the holiday season and emphasizing value throughout their marketing efforts," the NRF says in its release.

Some experts are decidedly less optimistic, however: Accenture says it expects to see a flat Christmas, with 83% of the consumers it surveyed planning to spend the same or less on gifts. And 87% say they won't be motivated unless they see discounts of 20% or more.

It's hard to overstate how important the holiday selling season is to retailers: For some, it can account for anywhere between 25% and 40% of annual sales.(Jewelry stores are among the most vulnerable.) Last year, holiday represented 19.1% of total retail industry sales, the NRF says.

It's also a passion for many people, with 79 million people in the U.S. storming the stores last Black Friday -- the day after Thanksgiving and the unofficial kickoff of the selling season-spending an average $343.10 per person during over Thanksgiving weekend. And then 96.5 million shopped online on Cyber Monday -- the Monday after Thanksgiving.

But the Accenture survey detects a growing consumer boredom with the frenzy, with 53% saying they are either not likely to shop on Black Friday or haven't decided, up from 48% last year. Some 69% say they will buy gifts online, up from 64% last year.

Last year, the NRF says retail sales inched up a scant 0.4% -- and in 2008, as the enormity of the recession settled in with consumers, sales fell 3.9%. (NRF includes November and December in its holiday sales figures, and excludes restaurant spending, as well as sales of cars and gas.)