In another encouraging sign for this year's holiday sales, employment in the retail industry is spiking.

According to the outplacement firm Challenger, Gray & Christmas, retailers hired 465,000 seasonal workers in the month of November, a 20% jump from last year . That's the biggest November hiring yet, and it puts the industry on pace for a record holiday season of employment gains.

Here's a look at total employment in the industry over the past year:

Source: Federal Reserve Economic Data

Retailers have been busy stocking up resources for what's already become a record holiday season of shopping. Amazon.com (AMZN -1.65%) announced in October that it would bring in 50,000 seasonal workers to help move products through its 40 fulfillment centers . Wal-Mart (WMT 0.57%) said it would hire 50,000 new associates for the holiday season, too . And Target (TGT -0.54%) said it expected to hire an additional 80,000 to 90,000 seasonal workers . Out of these three companies, only Target plans on hiring fewer additional workers this year than it did in 2011.

These companies had to staff for an unusually long season this year. Several retailers, including Target and Wal-Mart, opened for business earlier on Thanksgiving Day. That gamble paid off with consumers. Wal-Mart estimates that it handled more than 20 million customers that day alone.

And, thanks to where Thanksgiving fell on the calendar, this year's peak shopping season, between Thanksgiving and Christmas Day, is the longest possible amount of time for consumers to stuff their carts. There are 32 days in between the holidays this year, which would strain even the best-staffed merchants.

Looking ahead
Last year's seasonal hiring by retailers in December was about 150,000. If they just meet that figure again this year, it will make for the strongest Q4 hiring season since 2000 . Not only would that be a sign of strong sales this holiday, but it also means more money in consumers' pockets, which should fuel even more retailing gains.