Well then, it's time to start the countdown. ;)
https://www.gog.com/forum/general/local_prices_update/post672

i bet on tomorrow or it could be monday.

Monday, because they've just started a regular Weekend Sale.
(well, not exactly regular as it does not work, but there's an announcement)

Do you think we will see higher discounts or the usual ones ?

You know the answer.
¯\_(ツ)_/¯

With SEGA tweet teasing GOG at this time on a Sunday, I wonder if this year the sale will start at midnight (our time) like the other recent sales? Doubtful, I know.

Is Pentecost Monday not a public holiday in Poland anymore?

Never was.

It's Pentecost Sunday. Yes, it's a public holiday, but since Sundays are nonworking days anyway... ¯\_(ツ)_/¯

I'm not that old yet to forget what day it is.
I was just wondering about tomorrow (which is a public holiday around these parts) and the potential start of a bigger sale.

I may have been ignorant about Whit Monday as it's not a holiday in Poland. hangs his head ashamed

If the Summer Sale starts at midnight (Europe Zone) could be as an Imsonia, :)

So less than 3 hours left until the sale starts ?

I'm skeptical like SCPM. That'd be 6AM Poland time, and I think GOG would want staff up, awake, and focused for such a big sale with big new releases happening. I could be wrong though of course.

I agree with tfishell. It would be quite risky to launch a big event at Sunday midnight. Especially with GOG's tradition to make some mistakes, price bugs, missing announcements or incorrect sales' time-frames.

So I would not expect Summer Sale in 2 hours, but perhaps we can get some hints if e.g. there will be no new Weekly Sale? I'd rather bet for Monday 15:00 p.m. Polish time (when current flash deals expire) or even Wednesday (Warhammer sale ends in 2d 20h and its date is the last one from all active at the moment).