Dec. 19 is what UPS calls "Peak Day," its highest one-day volume of the year.
Volume for UPS air express delivery will actually peak two days later on Thursday, with a global volume of about 4.5 million packages. That's nearly double the average of about 2.3 million.
To handle the holiday season, during which UPS will deliver more than 325 million packages, UPS supplements its year-round workforce of 358,000 employees with up to 95,000 seasonal workers.
Despite the blizzard of holiday packages, UPS reported last week that it is expecting flat growth this month due to softening shipment volumes.