Since the forecast calls for rain throughout Thursday night, the women's semifinals (session 21) will be rescheduled for Friday, beginning at 11 a.m.
The gates of the Billie Jean King National Tennis Center will open at 10 a.m.
The changes also impact the men's semifinals (session 22), which will now begin at 5 p.m. instead of 3 p.m. on Friday.
Session 22 ticket-holders will be permitted on the grounds at 10 a.m., but will not be allowed to enter Arthur Ashe Stadium until after the women's semifinals.
In the women's semifinals, No. 1 Serena Williams will face unseeded Roberta Vinci and No. 2 Simona Halep will take on No. 26 Flavia Pennetta.
The men's semifinals will feature No. 1 Novak Djokovic against No. 9 Marin Cilic and No. 2 Roger Federer against No. 5 Stan Wawrinka.
Visit usopen.org for match times and more details.
- Kayla Lombardo