The claim is that every 823 years, there is a month with 5 Fridays, 5 Saturdays, and 5 Sundays. It happens in October 2010. But this is an internet hoax. October previously had 5 Fridays, 5 Saturdays and 5 Sundays in 1982, 1993, 1999 and 2004, and it will happen again in 2021. In fact, to my knowledge, there is NO calendar event [which is what this category pertains to] that regularly happens every 823 years. The Western world switched from the Julian to the Gregorian calendar more recently than that! (in 1582)
It is called Leap Year, and the day that is added is February 29th. We only get that day once every four years.
a leap year
Leap year happens once every 4 years. This is when there is a February 29th when in comparison to other years, there is only a February 28th.
That only happens when Easter falls on April 8, which happens on average once every 35½ years.
One example of an event that occurs once every four years is the Olympic Games. The Summer and Winter Olympics alternate every four years, providing athletes from around the world the opportunity to compete on a global stage. This quadrennial event showcases a wide range of sports and brings nations together in the spirit of competition and sportsmanship.
A false rumor is floating around the Internet that this happens only once every 823 years. The reality is that it happens whenever the first day of October is on Friday, which happens on average once every seven years. The last time for this "rare" event was 6 years ago, back in 2004. And the time before that was 5 years previously, in 1999.
The Mayans predicted on the day December 21, 2012 that a galactical allignment will take place. This happens only once every 25,000 years.
It only snows once in a blue moon. About once every few years.
every 4 years
Only once or twice in your life time, its not so, you need a booster shot once every 10 years superfuga
29th of February only happens in a leap year. So it only happens every 4 years.
February 29th