The Encore Weekend will begin Saturday, January 5 at 10am PT (6pm GMT) and run through the same time on Monday, January 7.
The daily deals during the extended sale will include "a select number of the most sought-after titles from the Steam Holiday Sale", according to Steam.
The Steam Holiday Sale launched on December 20, and was scheduled to end today, January 4.
It featured six new game deals each day, along with flash sales cycling every few hours and a community vote for additional deals.
For the final day of the sale the daily deals includes between 50% and 75% off Sleeping Dogs, Rage, Amnesia: The Dark Descent, the Crysis franchise, Forge and the Trine series.