UPS Cranks Up Its Sleigh for Dec. 18

United Parcel Servicehas predicted that date will be its busiest shipping day of the holiday season, while its busiest day for handling air packages will likely be Dec. 22, the company said.

Earlier this week, UPS ditched plans to forecast how many packages it expects to handle this holiday season, as it typically does. The company also omitted how many seasonal employees it will hire to help it through the holiday crunch, which runs from Thanksgiving until Christmas.

Last year, UPS, the world's largest shipping carrier, delivered more than 22 million packages on its peak shipping day, which fell on Dec. 19, and it hired about 60,000 seasonal workers.

UPS's silence on shipping volume and temporary hires marks another indicator of how unpredictable the retail landscape is this holiday season.

Retail sales have fallen for four straight months, with October's sales down 2.8 percent. Many analysts are now expecting that unless shoppers really start spending, sales for the holiday season are likely to fall short of many estimates.

• Gift Card Sales Seen Down 6%
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• Home Depot Profit Falls
• Wal-Mart: Lower Gas Prices Helping Traffic

The expected weakness in holiday shopping will add to slowing volume not only at UPS, but also at rivals FedEx and Deutsche Post's DHL unit.

Last month, UPS said its next-day volumes fell "precipitously" in September and it projected fourth-quarter volume to fall 4 percent from the year before as many business clients cut costs by shifting from air shipping to lower-cost ground service.

Recent Holiday Central Posts:

• Web Sales Tactics: Virtual Salespeople and Zombie Videos
• Tech the Halls: Gift Cards Get Gadgets to Lure Shoppers
• Why You Should Worry About Weak Holiday Sales
• Toy Trends: Lean and Barbie Green
• Christmas on Consignment: Luxe Without the Guilt—or the Pricetag
• Finally, a Cheery Holiday Forecast for Retailers

Questions? Comments? retaildetail@cnbc.com