It was narrated that Anas bin Malik said:
"The Messenger of Allah (ﷺ) used to pray Zuhr when the sun passed its zenith, and he would pray 'Asr between these two prayers; and he would pray Maghrib when the sun had set, and he used to pray 'Isha' when the twilight had disappeared," then he said straight after that: "And he would pray Fajr when a man could see clearly." (FR)
English reference (FR): Vol. 1, Book 6, Hadith 553 (FR)
Arabic reference (FR): Book 6, Hadith 557 (FR)