Steam Sales may come within three days
Gaming site Kotaku has recently confirmed these dates with three developer sources from Steam, therefore the leak is seemed to be quite reasonable.
The schedule for sale is as follows:
Halloween Sale: October 26, 2017- November 1, 2017
Autumn Sale: November 22, 2017- November 28, 2017
Winter Sale: December 21, 2017- January, 2018
If these are true, that means the most recent date for sale deals is October 26, at around 6pm GMT. However, it's worth nothing until Valve officially announced these sales .
But the Halloween is very soon , we can regard this leak as notice and just put what video games we want in shopping cart for now .