The Jews reckoned a day as beginning as sunset. Night was divided into "watches".
First watch – sundown to 9PM
Second watch – 9PM to midnight
Third watch – midnight to 3AM
Fourth watch – 3AM to sunrise
Exodus 14:24 And 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
Judges 7:19 So 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.
Psalm 63:6 When I remember thee upon my bed, and meditate on thee in the night watches.
Psalm 90:4 For a thousand years in thy sight are but as yesterday when it is past, and as a watch in the night.
Lamentations 2:19 Arise, cry out in the night: in the beginning of the watches pour out thine heart like water before the face of the Lord ...
Days begin with dawn and end with sundown. Length of days vary with the seasons.
First hour – dawn
Third hour – 9AM
Sixth hour – Noon
Ninth hour – 3PM
Matthew 20:3 And he went out about the third hour, and saw others standing idle in the marketplace.
Mark 15:25 And it was the third hour, and they crucified Him.
Acts 2:15 For these are not drunken, as ye suppose, seeing it is but the third hour of the day.
Matthew 20:5 Again he went out about the sixth and ninth hour, and did likewise.
Matthew 27:45 Now from the sixth hour there was darkness ...
John 4:6 Now Jacob's well was there. Jesus therefore, being wearied with His journey, sat thus on the well: and it was about the sixth hour.
John 19:14 And it was the preparation of the Passover, and about the sixth hour: and he saith unto the Jews, Behold your King!
Acts 10:9 On the morrow, as they went on their journey, and drew nigh unto the city, Peter went up upon the housetop to pray about the sixth hour
Acts 3:1 Now Peter and John went up together into the temple at the hour of prayer, being the ninth hour
Acts 10:3 He saw in a vision evidently about the ninth hour of the day and angel of God coming in to him, and saying unto him, Cornelius.
Acts 10:30 And Cornelius said, Four days ago I was fasting until this hour; and at the ninth hour I prayed in my house, and, behold, a man stood before me in bright clothing.