5 Weekends in 1 Month Happens More Often Than Every 823 Years

Before you get too excited about this once-in-a-lifetime event and start telling your family and friends, know this: any such claims are false. Combinations of days like 5 Fridays, 5 Saturdays, and 5 Sundays occur much more often than every 823 years!

The 823 Years Myth

If you have an email or a social media account, chances are that you have come across a viral post that claims an upcoming month has a rare combination of weekdays. Share it, the message states, or beware of some bad luck.

A recent version goes something like this:

“March 2024 has 5 Fridays, 5 Saturdays, and 5 Sundays. This happens only once every 823 years. The Chinese call it “silver pockets full” or “money bags.”

The email is partially correct. March 2024 does have 5 Fridays, 5 Saturdays, and 5 Sundays. But this is neither special nor unusual. You won’t need to wait another 823 years for this weekday combination.

A calendar month that contains 5 Fridays, 5 Saturdays, and 5 Sundays actually occurs nearly every year—August 2025, May 2026, and August 2026 all have the same weekday pattern.

First Day of the Month

The weekday combinations these 823-year messages refer to aren’t exceptional either. A quick look at a calendar will show that the first 3 weekdays of any 31-day month will be repeated 5 times in that month. So, any month that has 31 days and begins on a Friday will have 5 Fridays, 5 Saturdays, and 5 Sundays. Similarly, any 31-day month that begins on a Tuesday will have 5 Tuesdays, 5 Wednesdays, and 5 Thursdays.

Put it to the test in our calendar

Recurring Monthly Calendars

Ready for some math? Here’s a more mathematical reasoning of why the 823-year claim is a myth:

Every year has 7 months with 31 days. Each of these months has at least 3 weekdays that happen 5 times during the month. For example, January 2024 has 5 Mondays, 5 Tuesdays, and 5 Wednesdays. May 2024 has 5 Wednesdays, 5 Thursdays, and 5 Fridays.

There are 7 different days a month can start with. So, on average, the combination of any 3 days occurring 5 times in a calendar month will happen once a year.

In any given year, there are only 6 such combinations of days. This is because 2 months with 31 days start on the same weekday. In a common year, January and October have the same calendar, while January and July look the same in a leap year.

The Doomsday Rule for calendars

Topics: Fun, Dates