Let's see. There are 28,417 members here, less than 300 of whom have admitted to having September birthdays. Of the people who actually do admit when their birthday is, the months seem to be fairly evenly spread out (and January has the most, by far, of any month). Not such an huge amount for September (and even if there was, given that most northern hemisphere locations that actually experience cold months experience them roughly from about October to April, you'd have to come up with a better reason why there were so many September birthdays).
