November 18, 2022
The Steam Fall sale will run on November 22 to November 29. Then the Steam Winter sale will follow up not too far behind.
TLDRLIFE.COM
As per the changes on the Steam Sales:
Autumn Sale: Nov 22nd to Nov 29th
Winter Sale: Dec 22nd to Jan 5th
Spring Sale: March 16th to 23rd
Steam often run sales and publisher sales. But the seasonal sale is the time you've been waiting for to buy that game. As for myself, it would be the time to purchase a game-dev software.