Skip to content

Birthday Frequency Visualization

This is a beautiful visualization of birthday frequency:

This “heat map” shows which days are the most common birthdays in the U.S.

Lost of interesting questions arise from this representation of data.  We can immediately see that July, August, and September seem to form a disproportionate band of birthdays.  And take a look at July 4th:  what’s the explanation for that?

In addition, you could also use this chart to create some new twists on the classic birthday paradox!


  1. Paul Gitchos says:

    Because many births are scheduled and induced, weekday birthdays are more common. I think this would also explain the July 4 and Christmas holidays showing up on the chart.

    December 28 has always felt like an uncommon birthday to me, but now I know it’s much more common than the 26th.

    I really appreciate your blog. Thanks!

    • MrHonner says:

      Hi Paul-

      I think you’re right about scheduled births having a great influence on the dispersion of birthdays. Knowing what percentage of births were scheduledm, that is un-(?) or pseudo-(?) random, would help in this analysis. I wonder how high that percentage would have to be to impact the “random” distribution in general.

      Thanks for stopping by–and thanks for the kind words.

Leave a Reply