The Circuit of the Americas will be closed until midday local time (1800 BST) at the earliest "for the safety of fans and employees" as heavy rain and thunderstorms continue in Austin.
Heavy rain has forced the temporary closure of the circuit, following the cancellation of Friday afternoon's practice session after heavy rain meant the medical helicopter would not be able to take off.
Yesterday thunderstorms forced the cancellation of FP2 as the weather meant the medical helicopter would be unable to take off from the circuit if needed. COTA says further updates will be given later in the day.
For the safety of our fans and employees, today's opening has been delayed until noon. Further updates will be forthcoming. #USGP #COTA
— COTA (@circuitamericas) October 24, 2015