The date of his ﷺ passing:

Al-Thawri narrated—through Hishām ibn ʿUrwah, from his father, from ʿĀʾishah—that she said: Abū Bakr once asked me, “On which day did the Messenger of Allah ﷺ die?” I replied, “On Monday.” He said, “I hope to die on that same day,” and indeed he died on a Monday.

Ibn Luhayʿah narrated—through Khālid ibn Abī ʿImrān, through Hanish, from Ibn ʿAbbās—who said: “Your Prophet ﷺ was born on a Monday, was commissioned on a Monday, left Mecca on a Monday, conquered Mecca on a Monday, Sūrah al-Māʾidah was revealed on a Monday—‘Today I have perfected your religion for you’ (5:3)—and he passed away on a Monday.”

Some of this is disputed, for ʿUmar (may Allah be pleased with him) said that the verse “Today I have perfected your religion for you” was revealed on the Day of ʿArafah, which that year fell on a Friday. The same was reported by ʿAmmār ibn Abī ʿAmmār on the authority of Ibn ʿAbbās.

Mūsā ibn ʿUqbah said: He died on a Monday, after the sun had passed its zenith, at the new crescent of the month of Rabīʿ al-Awwal.

Sulaymān al-Taymī said: The Messenger of Allah ﷺ died on the tenth day of his illness; that was a Monday, two nights having elapsed of Rabīʿ al-Awwal. This was related by Muʿtamir from his father.

Al-Wāqidī said: Abū Maʿshar related to us—from Muḥammad ibn Qays—who said: The Prophet ﷺ was ill for thirteen days and died on a Monday, two nights into Rabīʿ al-Awwal, in the year eleven AH.

Al-Ṭabarī also reported, on the authority of Ibn al-Kalbī and Abū Mikhnaf, that he died on the second of Rabīʿ