The Messenger of Allah ﷺ went out when the sun had passed its zenith and prayed Zuhr.
أن رسول الله ﷺ خرج حين زاغت الشمس فصلى الظهر.
Bukhari reported it in the Book of Prayer Times (540), from Abu Yaman, who said, Shuayb informed us, from Zuhri, who said, Anas bin Malik informed me, and he related the hadith within a longer account, which will come later in the description of Paradise and Hell.Tirmidhi reported it (156) through the route of Abdul-Razzaq, who said, Mamar informed us, from Zuhri, with the same chain, and its wording was that the Messenger of Allahﷺ prayed Dhuhr when the sun had passed its zenith.This is evidence that the passing of the sun's zenith marks the beginning of the time for Dhuhr, and it is also evidence that it is preferable to pray it early.Tirmidhi said, this is a sahih hadith, and it is the best hadith on this subject.