“On the tenth day of the same lunar month [Tishri, Hyperberetaeus] they Fast till the evening…” (Antiquities 3.10.3)
Sukkot
“Upon the fifteenth day of the same month, when the season of the year is changing for winter, the law enjoins us to pitch tabernacles (i.e. booths) in every one of our houses…” (Antiquities 3.10.2)