Growth is expected to be flat in holiday-season hiring by U.S. companies — including retailers — this year. That is in large part because many retailers have already hired permanent employees in earlier rounds and need fewer temporary hands this season, according to Andrew Challenger, vice president of business development at global outplacement firm Challenger, Gray & Christmas.

During a recent appearance on the Knowledge at Wharton radio show, Challenger urged those who are looking for some of those temporary jobs to act quickly. “If you want to take advantage of this extra bump in hiring that happens at the end of the year, you’ve got to start now,” he said. “It takes a little while to get on the radar of potential employers. So anybody looking to be hired for any of those positions [must] jump on it as soon as [they] can.”

The Knowledge at Wharton show airs 10 a.m.-12 p.m. Eastern time Monday-Friday on Wharton Business Radio on SiriusXM channel 111.

In the 2014 holiday season, which runs from October through December, retailers added 755,000 jobs. That was 4% lower than the 786,000 temporary jobs created in the 2013 holiday season, according to a press release on this year’s hiring trends from Challenger, Gray & Christmas. Companies that have announced hiring plans for the 2015 holiday season include Amazon (100,000 jobs), UPS (95,000), Macy’s (85,000), Target (70,000), Kohl’s (69,000) and Walmart (60,000), according to data compiled by

“If you want to take advantage of this extra bump in hiring that happens at the end of the year, you’ve got to start now.”

Challenger explains why holiday-season hiring is projected to be lower this year, even as consumers are expected to have more spending power thanks to lower gas prices, strong job gains and wage increases. “Primarily, we’ve already had a lot of hiring in the economy,” he said. “Month after month [we’ve seen] steady job gains across retail and across manufacturing. As the country is approaching full employment at 5.1% unemployment, there are just not as many jobs to add.” Much of the hiring that would normally be done temporarily has been done permanently earlier in the year, he added.

Retail employment increased by 449,500 from March through August, up from 437,000 in the same period last year, Challenger, Gray & Christmas said, citing U.S. labor department data.

Another big reason that retailers need fewer hands this season is the surge in online ordering, said Challenger. “Not as much is done in stores where retailers and companies have to hire extra clerks and extra sales people for those showroom floors,” he noted. The job opportunities are moving to back-offices and warehouses, and logistics companies like UPS and FedEx have accounted for the big spikes in hiring in the last few years, he added.