Sahih al-Bukhari Book 9, Hadith 19
When we offered the Zuhr prayers behind Allah's Messenger (ﷺ) we used to prostrate on our clothes to
protect ourselves from the heat.
Abu Barza said, "The Prophet (ﷺ) used to offer the Fajr (prayer) when one could recognize the person sitting by him (after the prayer) and he used to recite between 60 to 100 Ayat (verses) of the Qur'an. He used to offer the Zuhr prayer as soon as the sun declined (at noon) and the `Asr at a time when a man might go and return from the farthest place in Medina and find the sun still hot. (The sub-narrator forgot what was said about the Maghrib). He did not mind delaying the `Isha prayer to one third of the night or the middle of the night."
"The Prophet (ﷺ) prayed eight rak`at for the Zuhr and `Asr, and seven for the Maghrib and `Isha prayers in Medina." Aiyub said, "Perhaps those were rainy nights." Anas said, "May be."