Many Happy Returns

It is hard to believe that October is almost here.

I have been remiss in not wishing many of my readers "Happy Birthday".

That is because September is the month that I have the best chance of wishing you "Happy Birthday" and being right.

A study of all births in the United States between 1994 and 2014 showed that September was the most popular birth month.

In fact, September has nine of the top ten birthdays for the entire  year. Those nine days are actually all between September 9 and September 20.

Source: https://www.birthdayrank.com/

If you turn back the clock 40 weeks it seems that mid-December is a popular period for conceptions to occur. 

Is it the cold weather or the holiday mood?

Here is a birth frequency date heat map. 

Source: https://www.birthdayrank.com/

The least common days to be born are all holidays: December 25 is the least common followed by January 1, December 24 and July 4. 

Source: https://www.birthdayrank.com/

This suggests to me that nature has been overridden by either a doctor who has other plans for the holiday or a family who does not like the idea of having their child's birthday overshadowed by other events.

Notice in the chart above the spike in births on December 28, 29 and 30? That might suggest some tax planning is also in play as well.

What about the most popular birthdays in other countries?

Let's look at Australia in the Southern Hemisphere.

December is in their summer season. July is in their winter. You might expect a different pattern on births if seasonality is a driving factor.

Curiously, the most popular birthday in Australia is September 17. September 23, 24 and October 1 are also in the top 5. 

It might suggest that the feelings of the holiday season has more influence than climate in conception.

Source: https://thenewdaily.com.au/news/national/2021/06/27/most-least-common-birthdays/

The least popular birthdays in Australia are December 25 and December 26 (Boxing Day which is a holiday in Australia).

Note that there is no surge in births in Australia in the last week of the year. In fact, December is the the least likely month for a birth in Australia.

You can also see that February, March, April do have a fairly high percentage of the most popular birthdays in Australia. Backing up nine months gives us May, June, July which are cooler climes Downunder. In fact, April 8 is the second most popular birthday and the only one in the Top 5 that does not correspond to conception in the holiday season.

In the United Kingdom September is also the most popular birthday month according to a study of all births from 1995-2017.

The five most popular birthday are all in late September in this order.

September 26

September 25

September 24

September 27

September 30

Nine months before? Christmas and Boxing Day (December 26).

Despite the differences in the charts above, the numerical differences between the most popular birthdays and least popular are not as great as you might be led to believe.

For example in the UK, the most popular day, September 26, sees an average of 1,974 births in the average year. There were still 1,422 births on Christmas Day. 

The same is true in the U.S. and Australia. You generally will only see a variation of 20%-25% between the most popular and least common birthdays. Nature still is (mostly) in control.

Happy Birthday and many happy returns no matter when the big day is!

Speaking of happy returns, thanks to all of my readers for consistently returning to read BeeLine's content.

For the second consecutive month, BeeLine will exceed 500,000 views.

Source: Google Analytics
As of 6;00 am 9/30/26

There is still time today to refer BeeLine to a friend as last month's record of 567,000 views is within reach.