For that to happen, the month has to be 31 days long and has to start on a Friday. Since there are 7 months with 31 days and one chance in 7 a month will start on a Friday ( roughly, due to leap years) there is about once yaer this will happen.
Next month has 5 Fridays, Saturdays, and Sundays.
Since
14.5% of all years have a January with 5 of (Fri-Sat-Sun),
14.25% of all years have a March with 5 of (Fri-Sat-Sun),
14.5% of all years have a May with 5 of (Fri-Sat-Sun),
14.5% of all years have a July with 5 of (Fri-Sat-Sun),
14.25% of all years have an August with 5 of (Fri-Sat-Sun),
14% of all years have an October with 5 of (Fri-Sat-Sun), and
14% of all years have a December with 5 of (Fri-Sat-Sun),
the average occurrence comes to exactly once per year.
About twice each year
The month of July has 5 Saturdays and 5 Sundays zerotimes in 2012.
4 years
there 5 sundays,mondays,saturdays in every 200 years
This happens on average of once every 7 years- 4 times in every 28-year cycle of the calendar. It happens whenever March first is a Friday..
March
ummm...never.
About twice each year
every 823 years.
Exactly 14% of all Decembers have five of each of Fridays, Saturdays and Sundays.
Never.
Every year has more than 5 Fridays, 5 Saturdays and 5 Sundays.
This happens in any 31-day month starting on Friday (such as July 2005).
once every 365 years!
The month of July has 5 Saturdays and 5 Sundays zerotimes in 2012.
According to my desktop calendar, July will have five Fridays and Saturdays (and even some Thursdays) in 2016, 2021, 2022, 2027,2032, 2033, etc... If you look at http://www.timeanddate.com/calendar/monthly.html?year=2021&month=7&country=1 you will see that 2021, 2027, 2032 do not have 5 Sundays. The other years 2016, 2022, 2033 do have 5 Fridays, Saturdays, and Sundays. You are little confused since your first parahraph discusses Fridays and Saturdays, in which case 2021 and 2022 do indead have 5 Fridays and 5 Saturdays in July. In paragraph two above, you begin talking about Sundays and which years in which July will 5 each of Fridays, Saturdays and Sundays. Every month with 31 days will have 5 instances of the first 3 days in the month. This will repeat in a 5-6-5-11 year cycle and then repeat. So it should be 2016, 2022, 2033, 2039, 2044, 2050, 2056 - don't forget to consider leap year which will cause a 1 day shift.
Every time February 1st falls on a Monday !