The Prophet ﷺ used to pray the Zuhr at midday, and the ʿAsr at a time when the sun was still bright, the Maghrib after sunset (at its stated time) and the ʿIsha at a variable time. Whenever he saw the people assembled (for ʿIsha' prayer) he would pray earlier and if the people delayed, he would delay the prayer. And they or the Prophet ﷺ used to offer the Fajr Prayers when it still dark.  

كَانَ النَّبِيُّ ﷺ يُصَلِّي الظُّهْرَ بِالْهَاجِرَةِ وَالْعَصْرَ وَالشَّمْسُ نَقِيَّةٌ وَالْمَغْرِبَ إِذَا وَجَبَتْ وَالْعِشَاءَ أَحْيَانًا۔ وَأَحْيَانًا إِذَا رَآهُمُ اجْتَمَعُوا عَجَّلَ وَإِذَا رَآهُمْ أَبْطَوْا أَخَّرَ وَالصُّبْحَ كَانُوا أَوْ كَانَ النَّبِيُّ ﷺ يُصَلِّيهَا بِغَلَسٍ  

When Hajjaj came to Medina we asked Jabir b. Abdullah (about the timings of prayer as observed by the Holy Prophet). He said: The Messenger of Allah ﷺ used to pray afternoon prayer in the midday heat; the afternoon prayer when the sun was bright; the evening prayer when the sun had completely set; and as for the night prayer, he sometimes delayed and sometimes (observed it) at earlier hours. When he found them (his Companions) assembled (at earlier hours) he (prayed) early. and when he saw them coming late, he delayed the (prayer). and the morning prayer the Messenger of Allah ﷺ observed in the darkness before dawn.  

كَانَ رَسُولُ اللَّهِ ﷺ يُصَلِّي الظُّهْرَ بِالْهَاجِرَةِ وَالْعَصْرَ وَالشَّمْسُ نَقِيَّةٌ وَالْمَغْرِبَ إِذَا وَجَبَتْ وَالْعِشَاءَ أَحْيَانًا يُؤَخِّرُهَا وَأَحْيَانًا يُعَجِّلُ كَانَ إِذَا رَآهُمْ قَدِ اجْتَمَعُوا عَجَّلَ وَإِذَا رَآهُمْ قَدْ أَبْطَئُوا أَخَّرَ وَالصُّبْحَ كَانُوا أَوْ قَالَ كَانَ النَّبِيُّ ﷺ يُصَلِّيهَا بِغَلَسٍ  

We asked Jabir about the time of the prayer of the Messenger of Allah ﷺ. He said: He used to offer the Zuhr prayer in the midday heat, the 'Asr prayer when the sun was bright, the Maghrib prayer when the sun had completely set, the Isha prayer early when many people were present, but late if there were few, and the Fajr prayer in the darkness (of the dawn).  

عَنْ وَقْتِ صَلاَةِ النَّبِيِّ ﷺ فَقَالَ كَانَ يُصَلِّي الظُّهْرَ بِالْهَاجِرَةِ وَالْعَصْرَ وَالشَّمْسُ حَيَّةٌ وَالْمَغْرِبَ إِذَا غَرَبَتِ الشَّمْسُ وَالْعِشَاءَ إِذَا كَثُرَ النَّاسُ عَجَّلَ وَإِذَا قَلُّوا أَخَّرَ وَالصُّبْحَ بِغَلَسٍ  

When Hajjaj came to Medina we asked Jabir b. Abdullah (about the timings of prayer as observed by the Holy Prophet). He said: The Messenger of Allah ﷺ used to pray afternoon prayer in the midday heat; the afternoon prayer when the sun was bright; the evening prayer when the sun had completely set; and as for the night prayer, he sometimes delayed and sometimes (observed it) at earlier hours. When he found them (his Companions) assembled (at earlier hours) he (prayed) early. and when he saw them coming late, he delayed the (prayer). and the morning prayer the Messenger of Allah ﷺ observed in the darkness before dawn. (Using translation from Muslim 646a)  

كَانَ رَسُولُ اللهِ ﷺ يُصَلِّي الظُّهْرَ بِالْهَاجِرَةِ وَالْعَصْرَ وَالشَّمْسُ نَقِيَّةٌ وَالْمَغْرِبَ إِذَا وَجَبَتْ وَالْعِشَاءَ أَحْيَانًا يُؤَخِّرُهَا وَأَحْيَانًا يُعَجِّلُ وَكَانَ إِذَا رَآهُمْ قَدِ اجْتَمَعُوا عَجَّلَ وَإِذَا رَآهُمْ قَدْ أَبْطَئُوا أَخَّرَ وَالصُّبْحَ قَالَ كَانُوا أَوْ قَالَ كَانَ يُصَلِّيهَا بِغَلَسٍ  

"Al-Hajjaj arrived, and we asked Jabir bin 'Abdullah, who said: 'The Messenger of Allah ﷺ prayed Zuhr at the time of intense heat, [1] and 'Asr when the sun was white and clear, and Maghrib when the sun set, and with 'Isha' it would depend - if he saw that the people had gathered, he would pray early, and if he saw that they had not come yet, he would delay it.'" [1] Meaning, at the earliest time. (Using translation from Nasāʾī 527)  

كَانَ رَسُولُ اللهِ ﷺ يُصَلِّي الظُّهْرَ بِالْهَاجِرَةِ وَالْعَصْرَ وَالشَّمْسُ بَيْضَاءُ نَقِيَّةٌ وَالْمَغْرِبَ إِذَا وَجَبَتِ الشَّمْسُ وَالْعِشَاءَ أَحْيَانًا كَانَ إِذَا رَآهُمْ قَدِ اجْتَمَعُوا عَجَّلَ وَإِذَا رَآهُمْ قَدْ أَبْطَأُوا أَخَّرَ