UPS delivery man Vinny Ambrosino prepares to deliver packages on Christmas Eve while wearing a Rudolf nose and antlers in New York. Both UPS and FedEx had shipping issues leading up to Christmas Day. (Carlo Allegri/Reuters) and United Parcel Service said Thursday that they would offer refunds to customers who did not receive their Christmas orders on time, after a larger-than-expected surge in last-minute online shopping caught the shipping giant off guard.

Customers who failed to get their deliveries by Christmas Day will get $20 gift cards and refunds on shipping charges, Amazon said. UPS also offered refunds on shipping costs. FedEx did not promise refunds but said it would work with people affected.

A combination of bad weather, shoppers waiting until the last minute and the overwhelming surge in online buying resulted in some packages not getting under the Christmas tree in time.

The wave of shipments was so large that a UPS spokeswoman said “the volume of air packages in our system exceeded the capacity in our network.” Customers who ordered shipments via air or internationally are entitled to refunds, spokeswoman Natalie Black said.

Wal-Mart and Kohl’s, which also have large online operations and reportedly experienced delays, did not respond to requests for comment.

Online sales were a bright spot in otherwise gloomy forecasts for the holiday shopping season, according to analysts. The National Retail Federation, a trade group, predicted a 15 percent increase from last year. Holiday sales were expected to rise by only 4 percent.

The last-minute surge that clogged UPS systems may mean that online sales exceeded even optimistic forecasts. Final numbers for the holiday shopping season will be out next month.

The short holiday season may also have played a part in the delivery crunch. There were six fewer days between Thanksgiving and Christmas this year than last year. More than 30 million Americans did not start shopping until after Dec. 9, according to a survey by the National Retail Federation. Nearly half of those surveyed said they planned to shop online. Over the Thanksgiving weekend, about 60 million Americans went to the Web for goods, according to the retail group.

Kent Hertzog, 34, said he bought his family gifts last week on, expecting them to arrive in time for Christmas. He’s still waiting.

Hertzog, who lives in Reading, Pa., said he tracked his shipment on the UPS Web site, which showed that the items were delivered at 5 p.m. Wednesday. But he hasn’t received them yet. His neighbors were also expecting packages, he said, but their delivery date was pushed back to Thursday.

The experience has been frustrating, Hertzog said. He couldn’t give his mother her Christmas gift.“It didn’t ruin the day, but now that [Christmas] is over, you still paid for items that are missing,” Hertzog said.

UPS, which had expected to ship more than 132 million packages last week, said that holiday demand was higher than forecast. On its Web site Thursday, the company said it was still “making every effort to get packages to their destination as quickly as possible.”

In an e-mailed statement,
FedEx said it did not experience any “major service disruptions.”

Neither UPS nor FedEx specified how many packages were delayed.

Amazon said its systems worked fine. “Amazon fulfillment centers processed and tendered customer orders to delivery carriers on time for holiday delivery. We are reviewing the performance of the delivery carriers,” Amazon spokeswoman Mary Osako wrote in an e-mail.

(Amazon founder Jeffrey P. Bezos owns The Washington Post.)