Boyd’s Bible Dictionary:

(wake). The Hebrew night was divided into three watches, indeed of hours. The first was called “the beginning of watches,” beginning at sunset and lasting till 10 P. M. (Lam. 2:1919Arise, cry out in the night: in the beginning of the watches pour out thine heart like water before the face of the Lord: lift up thy hands toward him for the life of thy young children, that faint for hunger in the top of every street. (Lamentations 2:19)): the second, the “middle watch,” from 10 P. M till 2 A. M. (Judg. 7:1919So Gideon, and the hundred men that were with him, came unto the outside of the camp in the beginning of the middle watch; and they had but newly set the watch: and they blew the trumpets, and brake the pitchers that were in their hands. (Judges 7:19)); the “morning watch,” from 2 A. M. till sunrise (Ex. 14:2424And it came to pass, that in the morning watch the Lord looked unto the host of the Egyptians through the pillar of fire and of the cloud, and troubled the host of the Egyptians, (Exodus 14:24); 1 Sam. 11:1111And it was so on the morrow, that Saul put the people in three companies; and they came into the midst of the host in the morning watch, and slew the Ammonites until the heat of the day: and it came to pass, that they which remained were scattered, so that two of them were not left together. (1 Samuel 11:11)). After the captivity the Jews gradually adopted the Greek and Roman division of the eight into twelve hours of four watches; “evening,” 6 to 9; “midnight,” 9 to 12; “cock-crowing,” 12 to 3; “morning,” 3 to 6 (Matt. 14:2525And in the fourth watch of the night Jesus went unto them, walking on the sea. (Matthew 14:25); Mark 13:3535Watch ye therefore: for ye know not when the master of the house cometh, at even, or at midnight, or at the cockcrowing, or in the morning: (Mark 13:35); Luke 12:3838And if he shall come in the second watch, or come in the third watch, and find them so, blessed are those servants. (Luke 12:38)).