The question comes around every four years: Why do we have Leap Year?
Every Leap Year, we have one extra day in February. (February 29).
We have 3 years with 365 days and then 1 year with 366 days,
and then 3 years with 365 days and so on.
So every fourth year we have one extra day. Why do we need
this extra day? Seems like a lot of hassle!
A year is how long it takes the earth to circle around (orbit) the sun.
Where earth is in relation to the sun determines the climate and the
seasons. Popular belief is that a year is exactly 365 days, which is
incorrect. A year is actually about 365 days 5 hours 48 minutes 46 seconds.
If we did not adjust with a leap year, the seasons would slowly change
at the rate of about 1 day per 4 years. Seasons would come later. For
instance, in 100 years winter would begin about 25 days later.
Also, since we add a day every 4 years, but 5 hours 48 minutes 46 seconds
times 4 is not quite one whole day, we occasionally have to adjust for that,
or the seasons would slowly creep in the other direction (earlier). We solve
that by not having Leap Year EVERY 4 years. Once in a long while, we skip
one.
To find out what years are not Leap Years, you have to look at the rules for Leap
Year: You probably know that the year must be divisible by 4 to be a leap
year. However, there are exceptions to that rule. A century year (a year that ends
in 00) is only a leap year if it is evenly divisible by 400. Which means:
1800, 1900, 2100, 2200, 2300, 2500, 2600, 2700, and so on are not leap
years.
