Let's make predictions! (:

I noticed that at least in the last six months the price matrix has been updated right before the start of any big sale.

For example, the price matrix was updated on December 9, 2019 and the winter sale started on December 11 (Monday). Then the matrix was updated on March 13, 2020 and the spring sale began on March 16 (Monday).

I guess that the sale will begin today and will last three weeks, just like a winter sale.

Less than an hour is left to find out if I'm right or wrong.

My guess is also today. 3 weeks would be great!
No reason to wait. It's the most comfortable schedule for GOG stuff. Kids are at home, a lot of people still work remotely. Steam sale is far away from here, so gaming budgets are full. There will be also no overlapping weekly/midweek/weekend sales.

Meh:
https://www.gog.com/promo/20200525_weekly_sale

Aaand, weekly sale. Seems my male intuition didn't deceive me.
Going by the price matrix change however, it might begin in Wednesday. Will see, it's all very exciting.

Why would there be a summer sale in May, especially when the Steam one is going to be rather late? 1st of June seems more likely, if not 8th.

Some time ago, GOG had a news item encouraging people to update their wishlist and they specifically mentioned that it's best to do it on May and December. Which led many, myself included, to assume that the Summer Sale will begin in late May. I would guess, this Thursday.

They have updated their exchange rates today, which is another hint that the Summer Sale will start within the next few days.

My guess would be this Thursday or Friday. But then there are the two weekly sales. So it also might be the next Monday, which still would fit to the "best update your wishlist in May".

And I still hope special offers will not be based on that crap newsletter email format with hidden discounts.

With the sale's start on next Monday, they'd update the price matrix on Friday. It must be this week! :)
Regarding discounts - for me no matter how they publish them. I hope they will be as good as the recent newsletter offers I've received (and used some of them).

We will see, but I think it may happen this Monday. But I'm more interested to know if there will be some big releases on this Summer Sale?

Well thought, today or tomorrow i guess we will leave doubts.

Personally I would like to see summer sale at least one or two weeks later. But it seems that will start within couple of days.

I've got my paycheck. We can start right now.
However now the most probable scenario is Thursday or Friday, with 48h freebie madness ending in the upcoming weekend (my vote for Thimbleweed scenario, Paraharaha!).
Let's see if there will be a new Midweek Sale today.

1st June in Poland is Children's day, so probably we should expect the sale around that date.

Fixed that for you!

Except if you were referring to the actor!