When the sun passed its zenith, the Messenger of Allah ﷺ would pray Dhuhr, reciting something close in length to "By the night when it covers" [Layl 92:1]. He would do the same for Asr and the other prayers, except for Fajr, which he would lengthen.
حدثنا عبيد الله بن معاذ حدثنا أبي حدثنا شعبة عن سماك سمع
كان رسول الله ﷺ إذا دحضت الشمس صلى الظهر وقرأ بنحو من والليل إذا يغشى والعصر كذلك والصلوات كذلك إلا الصبح فإنه كان يطيلها
No references are available.
Muslim reported it in Sahih Muslim, Book of Prayer, Chapter on the Recitation in the Dawn Prayer, no. 459, from the hadith of Shubah, with this chain.