The standing at عرفات (wuquf) is the greatest pillar of حج, as نبی کریم (صلی اللہ علیہ وسلم) said: 'حج is عرفات.' Its time begins after zawal (when the sun passes its zenith) on the 9th of Dhul-Hijjah جمہور علماء کے مطابق, and extends until the dawn (fajr) of the 10th of Dhul-Hijjah. A حاجی who is present at عرفات for even a moment during this time window has fulfilled the pillar of حج.
Sheikh Ibn Baz explained that the Sunnah is to arrive at عرفات before zawal, pray Dhuhr and Asr combined and shortened, and remain there supplicating until sunset. However, a حاجی who arrives late — even in the last moments before fajr of the 10th — has caught عرفات and their حج is valid. نبی کریم said: 'Whoever comes to عرفات before dawn on the night of Jam' (مزدلفہ), his حج is complete.' This hadith establishes that the nighttime of the 9th is also valid time for wuquf.
Sheikh Ibn Uthaymeen noted that while arriving late at night is valid, the حاجی who only stands at عرفات at night misses the Sunnah of daytime standing and the great merit of دعا on the afternoon of عرفات. He مستحب every effort to arrive during the daytime. If a حاجی arrives after sunset but before fajr, their standing is valid but they should offer a dam (sacrifice) according to some scholars, as they missed the daytime standing. However, the majority hold that no dam is required as long as any part of the wuquf window was caught.