Jesus was arrested on the night of what is traditionally considered the beginning of Passover, which would have been Thursday evening, March 30, 33 AD.
The arrest took place in the Garden of Gethsemane after Jesus and his disciples had shared the Last Supper, which was a Passover meal according to the Synoptic Gospels (Matthew, Mark, and Luke). This sets the timeline of his arrest shortly after the Passover meal, leading into Friday morning when he was brought before various Jewish and Roman authorities.