Generally, birthdays are pretty evenly distributed throughout our 12-month calendar according to a public records database of American births. It has been documented, however, that more birthdays fall (ahem) in September and October. In fact, more people have their birthdays on October 5 than any other day. Insightful researchers accounted for this by simply counting back nine months to early January. The holiday season has everything to do with these tendencies, as well as it bringing the Northern Hemisphere’s longest nights of the year.