Why would a sale from the middle of December to the beginning of January be called winter sale rather than Christmas sale? Winter has barely even started yet and it is summer in the southern hemisphere. Most of the shopping will be related to Christmas gifts one way or another, or simply be bought because many people get time off due to the holidays.
There's even faint hints of Christmas, but it is as if it is the season who can not be named.

Obviously you can call your own sale what ever you want, but it makes little sense.

What's the story?

They're a worldwide store and not everyone celebrates Christmas.... that would be my guess. Kind of the same reason they would have a summer sale not a 4th of July sale, cause it's only applicable to one market segment instead of the entire market.

My guess is that it's calculated to be as generic as possible from a marketing perspective.

The end point of the sale is just after New Year's Day, so perhaps they consider it a combined Christmas + New Year holiday season sale.

Cause GOG with the rest of the gaming industries is waging a secret war on Christmas, duh!

I don't see much of a point in naming it something that is irrelevant to anyone that's not Christian, and associating their business with a specific religion. Generic naming is safer and applies to a broader demographic.

They have spring, summer, and fall sales, why leave out winter? Also technically it's not even winter yet and won't be for 10 days, but all of their seasonal sales are ahead a little like that.

Going solely by official dates, sure. But I can tell you, in terms of weather and temperature, it is definitely winter where I am, and has been for some time.

Never quite understood different definitions of Winter.
In my mind, astronomically, December 21st (Winter Solstice) would be the middle of winter (another name for the Winter Solstice is literally "Midwinter").

So, astronomically speaking, the southern hemisphere doesn't exist?

Not to mention that even Christians shouldn't be all too happy about having big commercial store sales named after their holy feast days, provided they still remember the original meaning, which I believe was not shopping for presents ... ;)

Btw, I actually doubt that most of the shopping here would be related to Christmas presents. Of course I might be wrong - are you guys all buying cheaply discounted GOG gifts to give to your friends and family on Christmas? I hardly even know anyone in RL that would know what to do with them, letalone rejoice over getting them. ;)

Here, a few weeks ago it was winter, then it was spring, then winter, then spring, and now winter again. Given the increasing inability of the weather to decide what it is anymore, I'll go by the official dates. ;)

I wish my wife played games. It would make her easier to shop for.

I don't have any numbers related to buying motivation in December; but there's also the end-of-the-year bonus that some(?) employees get.

It's a Masonic conspiracy, they're trying to undermine the faith.

Nah, seriously, it's an international store, and tbh, buying lots of stuff isn't really in the spirit of Christmas anyway imo.