There is a specific marker of the day of the birth, which is the night that is no night. However, there were other omens in the heavens and on earth that had been prophesied. These signs also came to prepare the world. It is most likely that when “angels did appear unto men, wise men,” that they were appearing to the believers. Those who understood and believed could see the signs and understand them. The disbelievers continued to ignore the signs, and continued to be reject the gospel.
Chronological: The ninetieth year of the reign of the judges is approximately 6 BC, or two years prior to the birth of the Messiah.