Is this February special? No; it is just ordinary

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

07 February 2016

A friend forwarded to me a message proclaiming that this February is unique in that it has 4 Sundays, 4 Mondays, 4 Tuesdays, etc. Apparently, this special phenomenon occurs only once every 823 years. But before I could reply to him, he sent a follow up in which he said that he had checked his calendar and found that this month actually has 5 Mondays! So, he correctly concluded that the original message was a hoax.

This incident demonstrates how easy it is to check whether the strange things we read in the Internet Social Media are true. In this particular instance, many people have fallen for the lie and gone ahead to “forward if to 5 people or 5 groups…within 11 minutes” as instructed. They hope to get many bags of money after doing that: what a shame!

The incident also demonstrates the magnitude of junk doing the round in modern communications networks. Back in the day, when Microsoft was the only email server in the world, they did a survey and found that over 80% of messages processed were useless chain-letters. I doubt if that ratio has changed to date.

If you forward a message to 5 people then the five send to another 5 each, the message will be in the in the hands of over 12,000,000 people by the end of the tenth level in the series.

Now, if you think about it; only a month with 28 days should have exactly 4 Sundays, 4 Mondays, 4 Tuesdays, etc. The reason is simple: a week has seven days and 7 x 4 = 28. So, in reality, the so-called, unique phenomenon is more common than not. After all, there are a lot more 28-day Februarys that 29-day ones.

Nevertheless, this year’s February has 5 Mondays but four each of all the other days. The next time we get another such February will be after 28 years; that is in the year 2044. Again, the reason is quite simple: there is a leap year every four years and seven days per week, thus 7 x 4 = 28.

Inside every century, the calendar repeats a 28-year cycle. For example, the calendar for 2044 will be identical to that of 2016. Then 2045 will be the same as 2017 and so on. However, the cycle will break down in 2100 because that will not be a leap year.

If you didn’t know; a centruty year has a 29-day February only if it is divisible by 400. Thus 1900 was not a leap year and neither will 2100. 2000 was a leap-year because 2,000 divided by 400 is 5.

For this reason, the calendar repeats an 11,200-year cycle – 28 years time 400 = 11,200. But still; this is before we account for the date of Easter. The cycle of Easter dates repeats after 5,700,000 years!