Urwah bin al-Zubayr (may Allah have mercy on him) said: I heard Bashir bin Abi Mas'ud al-Ansari (may Allah be pleased with him) narrating from his father: "I saw the Messenger of Allah (peace and blessings be upon him) praying Zuhr when the sun had passed its zenith, and sometimes he (peace and blessings be upon him) delayed it when the heat became intense. And I saw him (peace and blessings be upon him) praying Asr while the sun was high and white, before any yellowness entered it, so that a man would finish his prayer and reach Dhu al-Hulayfah before sunset. He would pray Maghrib when the sun had set, and pray Isha when the horizon turned black, and sometimes he delayed it until the people gathered. He would pray the morning prayer in the darkness; then once he prayed it when it had become light; then after that his (peace and blessings be upon him) prayer was in the darkness until he (peace and blessings be upon him) passed away, and he (peace and blessings be upon him) did not go back to (praying it in) the light."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2045