Holiday Central

Retailers' Black Friday and Thanksgiving hours

Happy Thanksgivukkah!

It's the ultimate holiday mashup: Thanksgivukkah-BlackFriday.

During what's shaping up to be a highly promotional holiday season, many companies are choosing to move their in-store Black Friday deals a day earlier to Thanksgiving—a phenomenon many are calling Gray Thursday. That also happens to be the first full day of Hanukkah.

Online deals have begun even earlier, led by discount giant Wal-Mart Stores kicking off its sales in early November. Kmart and Sears will also hold early online deals for certain customers.

Black Friday creep first gained traction in 2010, when Sears opened its doors on Thanksgiving. Since then, the trend has intensified as retailers seek to one-up each other during what Wal-Mart U.S.'s chief merchandising and marketing officer, Duncan Mac Naughton, terms its "Super Bowl."

Retailers face several challenges this season, including slumping consumer confidence, a low employment participation rate and the shortest holiday calendar since 2002, with one less weekend.

For a guide to what stores are opening when, check out CNBC's list of store openings on Black Friday and Thursday:

—By CNBC's Katie Little. Follow her on Twitter @KatieLittle.