Personally I’m of the opinion it should be localized to whatever locale you are in if possible. So I look for New Moons locally and this can affect the date of holidays in the continental United States.
“And it shall be from new moon to new moon And from sabbath to sabbath,All mankind will come to bow down before Me.” – Isaiah 66:23 New Moon Watch New Moon Watch
Exegesis of Colossians-ii-13-17 And although you were dead in your sins and the uncircumcision of your flesh, he quickened [you] together with himself, forgiving us all the trespasses, blotting out the handwriting with the decrees which was against us, which was an adversary to us, and he removed it from the midst, nailing it to the cross. Having spoiled the principalities and the powers, he made a show of them […]