exvigilare

September 1 is the first day of the ecclesiastical new year. From the GOARCH website:

Since the completion of each year takes place, as it were, with the harvest and gathering of the crops into storehouses, and we begin anew from henceforth the sowing of seed in the earth for the production of future crops, September is considered the beginning of the New Year. The Church also keeps festival this day, beseeching God for fair weather, seasonable rains, and an abundance of the fruits of the earth.

The Holy Scriptures (Lev. 23:24-5 and Num. 29:1-2) also testify that the people of Israel celebrated the feast of the Blowing of the Trumpets on this day, offering hymns of thanksgiving.

Heck, if there are trumpets involved….