A new promotional image used by PayPal has announced that Steam’s Winter Sale is scheduled to begin Dec. 22, according to Shacknews.
The online payment processor revealed the date via a banner ad on their website, which we've included below. If Valve sticks to the model introduced during the previous sale in November you can expect new batches of discounted games to be announced daily and for those prices to be honored over the course of the entire week. We wouldn't be surprised if the new Steam controller or streaming device showed up at a discount either.
Shacknews is also estimating that the Steam sale will end on Dec. 30, just in time to get those purchases on the books for your 2015 tax write offs.