Steam sale dates usually get leaked weeks or sometimes months before the sale actually happens.
This time around, Valve just revealed the dates themselves leading up to the Autumn and Winter sales happening on November 24 to 30, 2021 and December 22, 2021 to January 5, 2022 respectively.
The company has put up a page called “Upcoming Steam Events”, with the first title on the page being Steam Next Fest that took place earlier this month.
The closest event happening on Steam is the annual Halloween Sale happening 28 October to 1 November 2021.
Of course these are dates for Steam’s platform wide sale. Publisher sales are likely to occur between those dates.
That being said, set reminders and prepare your bank accounts to buy more games that you won’t play. That stack of remorse in your PC is not going to grow on it’s own.