Oktoberfest is an annual event, and the event is celebrated from mid to late September into early October. It lasts sixteen days at the minimum, and eighteen days at its longest. It ends on the first Sunday of October, unless October 1 or October 2 is a Sunday, then it ends on Monday. This is a fun celebration, and one does not have to be German or Austrian to attend. It is a time for music, food, and drink. While it began years ago as a wedding feast for Crown Prince Ludwig in 1810, it has evolved into a heritage celebration.
In the local Oktoberfest, which is done for three weekends in October, not quite the traditional time, both German and Bavarian flags are flown. To be accurate, the origins of Oktoberfest was in the area of Bavaria, currently one part of Germany, so the blue and white diamond shapes of the Bavarian flag are best associated with the festival.