How many Sundays in a month of 30 days

5 Fridays, 5 Saturdays, and 5 Sundays in a month? It happens only once every 823 years! This popular urban myth has been circulating the internet for a while. However, it is precisely that: a myth.

Busting the "5 Fridays, 5 Saturdays, & 5 Sundays in 1 month" myth.

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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:

July 2022 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. July 2022 does have 5 Fridays, 5 Saturdays, and 5 Sundays, and so does December 2845, 823 years after. But this is neither special nor unusual. You won't need to wait for another 823 years for this weekday combination to occur. A calendar month that contains 5 Fridays, 5 Saturdays, and 5 Sundays actually occurs nearly every year—December 2023, March 2024, August 2025, and May 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, August 2022 has 5 Mondays, 5 Tuesdays, and 5 Wednesdays. December 2022 has 5 Thursdays, 5 Fridays, and 5 Saturdays.

There are 7 different days a month can start. 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

5-Day Combinations in a Month

Topics: Calendar, Fun

›› How many Sundays are there in 2020?

There are exactly 52 Sundays in the year 2020.

The answer to this question is not always simple. Most of the time, it will equal the number of weeks in a year, but that's only true for some of the days of the week.

Most years have 365 days, but a leap year has 366 days. That adds up to 52 weeks (where each week is exactly 7 days) PLUS 1 or 2 additional days. The year 2020 has exactly 366 days.

Now if the year starts on a Sunday in a non-leap year, you end up with 53 Sundays. Or if either of the first two days lands on a Sunday during a leap year, then you can also get 53 Sundays. Check the calendars below for January and December of 2020 to see exactly where the year starts and ends.

›› January, 2020 calendar

January 1st, 2020 is a Wednesday. It is the 1st day of the year, and in the 1st quarter of the year. There are 31 days in this month. 2020 is a leap year, so there are 366 days in this year.

›› December, 2020 calendar

December 31st, 2020 is a Thursday. It is the 366th day of the year, and in the 4th quarter of the year. There are 31 days in this month.

›› How Many Days calculator

This site provides a tool to count the number of any selected day of the week over an entire year. You can pick any year and find out things like the number of Sundays in 2022.

Don't forget to check out the other date calculator tools available on the site, like the Days From Today calculator that helps you find the date occurring exactly X days from now. Or if you're trying to count the total number of days between two dates, you can use the Date Difference calculator.

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