Until he obrerved the dawn prayer. Yahya (another narrator) said: Until it was dawn.
Sahih Muslim Book 15, Hadith 250
← Previous Hadith A'isha (Allah be pleased with her) reported that Allah's Messenger (ﷺ) entered Mecca during the year of Victory from Kada I. e. from the upper side. Hisham said.. My father entered It from both the Fides, but generally he entered from Kada.

Sahih Muslim Book 15, Hadith 249 Next Hadith → Nafi' reported that Ibn Umar (Allah be pleased with them) did not enter Mecca without spending the night at Dhi Tawu until it was dawn, when he took a bath, and then entered Mecca in the morning, and made a mention that Allah's Apostle (ﷺ) did that.

Sahih Muslim Book 15, Hadith 251