Herod died, according to historical records in 4 BC. And Jesus was born just before the death of Herod according to the Gospels (Matthew 2:19, 20). And Jesus was baptized when He was about 30 years old according to Luke (Luke 3:23). So that puts Jesus baptism at AD 27, 30 years from 4 BC.
Proof 3: The fifteenth year of Tiberius CaesarLuke records the baptism of Jesus to be in the fifteenth year of Tiberius Caesar (Luke 3:1, 21). According to historical records the 15th year of Tiberius Caesar was AD 27.
Proof 4: The Building of the TempleWhen Jesus visited Jerusalem temple for the first time after His Baptism in the month of Abib, the first Jewish month, He had a discussion with the leaders of the Jews. He said, “Destroy this temple, and in three days I will raise it up” (John 2:19). To which they replied that the temple was in construction since 46 years, and how could He build it in 3 days. From historical records we know that Herod started to rebuild the temple in 19 BC. And 46 years later would put the baptism year of Jesus to be AD 27.
And it was the preparation of the passover, and about the sixth hour: and he saith unto the Jews, Behold your King! But they cried out, Away with him, away with him,crucify him. John 19:14-15 (The "preparation day" in scriptures, is always in reference to the day of Passover on the 14th. They must prepare not only for the Passover meal that night, but also the Feast of Unleavened Bread the following day.)