When is the next sale?
The big seasonal sales at Steam and GOG. A sale with its dates is the store's announced dates; the others show when the sale usually happens, until the store announces them. Smaller sales and weekly deals happen all year: see all deals on sale right now.
Add these dates to my calendar
Your calendar app subscribes once and keeps the dates up to date, with a reminder the day before each sale. Only dates the store has announced are added; the others join once they are confirmed. Download the file instead.
Steam
GOG
Winter
Steam: to be announced
NovlateusualGOG Black Friday saleUsually late NovemberNot announced yet
DecearlyusualGOG Winter SaleUsually December to early JanuaryNot announced yet
Autumn
OctearlyusualSteam Autumn SaleUsually late September to early OctoberNot announced yet
GOG: to be announced