3 am to 6 am. According to what I can find.
Geneva Study Bible
And in the {c} fourth watch of the night Jesus went unto them, walking on the sea.
(c) By the fourth watch is meant the time nearer to day break: For in ancient times they divided the night into four watches in which they posted watches.
People's New Testament
14:25 In the fourth watch. The Jews, who used to divide the night into three watches, latterly adopted the Roman division into four watches, as here; so that, at the rate of three hours to each, the fourth watch, reckoning from six p.m. Would be three o'clock in the morning.
Jesus went unto them. The Lord saw their trouble from his mountain-top, and through the darkness of the night, for his heart was all with them; yet would he not go to their relief till his own time came.
Wesley's Notes
14:25 The fourth watch - The Jews (as well as the Romans) usually divided the night into four watches, of three hours each. The first watch began at six, the second at nine, the third at twelve, the fourth at three in the morning. If it be thou - It is the same as, Since it is thou. The particle if frequently bears this meaning, both in ours and in all languages. So it means, John 13:14,17. St. Peter was in no doubt, or he would not have quit
Geneva Study Bible
And in the {c} fourth watch of the night Jesus went unto them, walking on the sea.
(c) By the fourth watch is meant the time nearer to day break: For in ancient times they divided the night into four watches in which they posted watches.
People's New Testament
14:25 In the fourth watch. The Jews, who used to divide the night into three watches, latterly adopted the Roman division into four watches, as here; so that, at the rate of three hours to each, the fourth watch, reckoning from six p.m. Would be three o'clock in the morning.
Jesus went unto them. The Lord saw their trouble from his mountain-top, and through the darkness of the night, for his heart was all with them; yet would he not go to their relief till his own time came.
Wesley's Notes
14:25 The fourth watch - The Jews (as well as the Romans) usually divided the night into four watches, of three hours each. The first watch began at six, the second at nine, the third at twelve, the fourth at three in the morning. If it be thou - It is the same as, Since it is thou. The particle if frequently bears this meaning, both in ours and in all languages. So it means, John 13:14,17. St. Peter was in no doubt, or he would not have quit