Although there is no regular timeline, in the past you have often seen tools introduced in Europe a few months or more before they come to America. Some of their tools never make it over here, however, like the Belt Sander, or the Rustofix, or the Sword Saw.
I seem to feel like October and July often end up being the preferred introduction dates, but I'm sure someone can point out other months that have seen the introduction of new tools.
The only regular thing you can expect with Festool is the annual price increase, which not even a pandemic could stop but only delay this year.