5 Weekends in 1 Month Happens More Often Than Every 823 Years
5 Fridays, 5 Saturdays, and 5 Sundays in a month – happens only every 823 years? This popular urban myth has been circulating on the internet for a while. However, it is precisely that: a myth.
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. Special 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 own an email, Twitter, Facebook or any other social media account, chances are that you have come across an email or a post that claims an upcoming month has a very rare specific combination of days. A recent version goes something like this:
May 2020 will have 5 Fridays, 5 Saturdays, and 5 Sundays. This happens only once every 823 years. The Chinese call it “silver pockets full.”
The email is right in that May 2020 has 5 Fridays, 5 Saturdays, and 5 Sundays. But this is nothing special or unusual. You will not have to wait another 823 years for the next time this happens in the month of May. Only 6 years later, in 2026, May also has 5 Fridays, 5 Saturdays, and 5 Sundays.
Nearly Every Year
In fact, a calendar month that contains 5 Fridays, 5 Saturdays, and 5 Sundays occurs nearly every year.
In fact, the calendar 823 years in the future is not even the same as the calendar of the month in the many versions of the hoax! For instance, March 2019 had 5 Fridays, 5 Saturdays, and 5 Sundays. 823 years later, March 2848 has 5 Sundays, 5 Mondays, and 5 Tuesdays.
Not So Special
The combinations of days these messages or emails refer to are also not very special. This is because the first 3 weekdays of any 31-day month are 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.
Recurring Monthly Calendars
Here's a more mathematical reasoning 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, March 2019 had 5 Fridays, 5 Saturdays, and 5 Sundays. January 2019 had 5 Tuesdays, 5 Wednesdays, and 5 Thursdays.
There are 7 different days a month can start on. 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 in a leap year, January and July look the same.
5-day Combos in the Same Month
|On dates:||1 / 8 / 15 / 22 / 29||2 / 9 / 16 / 23 / 30||3 / 10 / 17 / 24 / 31||Comments|
|January 2019||5 Tuesdays||5 Wednesdays||5 Thursdays||Same as October 2019|
|March 2019||5 Fridays||5 Saturdays||5 Sundays|
|May 2019||5 Wednesdays||5 Thursdays||5 Fridays|
|July 2019||5 Mondays||5 Tuesdays||5 Wednesdays|
|August 2019||5 Thursdays||5 Fridays||5 Saturdays|
|October 2019||5 Tuesdays||5 Wednesdays||5 Thursdays||Same as January 2019|
|December 2019||5 Sundays||5 Mondays||5 Tuesdays|
|January 2020||5 Wednesdays||5 Thursdays||5 Fridays||Same as July 2020|
|March 2020||5 Sundays||5 Mondays||5 Tuesdays|
|May 2020||5 Fridays||5 Saturdays||5 Sundays|
|July 2020||5 Wednesdays||5 Thursdays||5 Fridays||Same as January 2020|
|August 2020||5 Saturdays||5 Sundays||5 Mondays|
|October 2020||5 Thursdays||5 Fridays||5 Saturdays|
|December 2020||5 Tuesdays||5 Wednesdays||5 Thursdays|