There's almost 8 billion people in the world and in the US, there's over 300 million people. The chances that one person will have the same birthday as someone else in the same neighborhood, town, or city, for example should be astronomically small, right?
Actually, the birthday paradox says something a bit different. When there is a group of 23 random people, the chances that two people will have the same birthday is 50%. Not only that, the probability increases by adding more people into the group. What are the odds?
So, with this tidbit in mind, you may be wondering, what is the most common birthday in the US? That would be September 9th. A couple runners-up to it are both from the same month, September 19th and 12th.
You may wonder why this is the case. If we count backwards nine months before, well, that would bring us to December, wouldn't it? And generally, apart from bringing merry good cheer to all people around during the season, it brings even merrier cheer to people in romantic relationships.
Some celebrities who were born on September 9th include Adam Sandler, Hugh Grant, Michael Bublé, Zoe Kazan, Constance Marie, and Michelle Williams. Now, although September fills the top ten list of most common birthdays, it's not actually the most common birth month.
That title belongs to August, and then July comes after, and then September. The three least common months are November, April, and February.
On the other hand, the rarest birthday, excluding February 29th, since that only happens every four years, is surprisingly December 25th. Now, what are the odds of that?
(Image credit: Robert Anderson/Unsplash)