Regarding Formula 1:
The ten fastest drivers of the qualifying have to use the tires of the second qualifying (Q2) at the start of the race. So they can’t change tires between Saturday and Sunday.
Quote from the Formula 1 regulations:
„With the exception of any cars that are required to start the race from the pitlane, at the start of the race each car which qualified for Q3 must be fitted with the tyres with which the driver set his fastest time during Q2. This will only be necessary for these cars if dry- weather tyres were used to set the fastest time in Q2 and if dry-weather tyres are used at the start of the race.“
Q2 would mean this or next month if you go for the quarters of the year.
So my guess is an announcement in June.
