Anas said that when it was very cold the Prophet observed the prayer early, and when it was very hot he delayed the prayer till it was cooler. The reference is to the Friday prayer. Bukhari transmitted it.
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 1403
Hadith Gradingالألبانی:صَحِيح | زبیر علی زئی:صحيح
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «رواه البخاري (906)»