Sahih al-Bukhari 3258
صحيح البخاري#3258SahihNarrated Abu Dhar:While the Prophet (ﷺ) was on a journey, he said (regarding the performance of the Zuhr prayer), "Wait till it (i.e. the weather) gets cooler." He said the same again till the shade of the hillocks extended. Then he said, "Delay the (Zuhr) Prayer till it gets cooler, for the severity of heat is from the increase in heat of 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: 59:68