Sahih al-Bukhari 538
صحيح البخاري#538SahihNarrated Abu Sa`id:that Allah's Messenger (ﷺ) said, "Pray Zuhr prayer when it becomes (a bit) cooler as the severity of heat is from the raging of the Hell-fire
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 9:15