And in the fourth watch of the night he came to them, walking on the lake.a Bible other translations
Between 3 and 6 a.m. In NT times, the day was divided into 12 hours (John 11:9) and the night into 4 watches: 1st: 6-9 p.m.; 2nd: 9 p.m.-midnight; 3rd: midnight-3 a.m.; 4th: 3-6 a.m. (Mark 13:35).

“fourth watch of the night.” At the time of Christ, both the Jews and Romans divided the night into four watches, each being three hours long: 6-9 p.m., 9-12 p.m., 12-3 a.m., and 3-6 a.m. So the fourth watch of the night started at our 3 a.m. (see commentary on Mark 6:48 and 13:35). So this is sometime between 3 a.m. and 6 a.m. Since the Apostles had started sometime before sunset (Mark 6:47) and it was now at least 3 a.m., so the Apostles had been rowing for at least six hours to go about 5 or 6 miles.

Commentary for: Matthew 14:25