That means Zechariah would have been ministering in the Temple in June, when it was officially the turn of Abijah. If his wife therefore conceived in June, John the Baptist would have been born around March the next year close to Passover. It is the Jewish tradition to reserve a special glass of wine for Elijah during the Passover meal, in expectation of his attendance. So, it makes sense for John the Baptist to be born during the Passover.