Everyone knows that leap years come once every 4 years. Unless the year is divisible by 100, then it’s skipped. Unless, of course, that year is also divisible by 400, then there is a leap day. (For example, 1600 and 2000 were leap years, but 1700, 1800 and 1900 were not.) Confused? It’s simple really. 365 + 1/4 – 1/100 + 1/400 = 365.2425, or 365 days, 5 hours, 49 minutes, and 12 seconds. Got it now?
All of this was done so the Gregorian calendar would keep the vernal equinox on or close to March 21, so that the date of Easter remains correct with respect to the vernal equinox. The vernal equinox year is about 365.242374 days long, a slight difference to the Gregorian calendar’s 365.2425, which will result in the calendar being off by 1 day in about 8,000 years. Maybe in February of 10008 there will be a February 29th and 30th! (Of course, maybe by then there will be an entirely new system of keeping time…)
Not every culture uses the Gregorian calendar, however. Some lunisolar calendars, such as the Chinese and Hebrew calendars, have leap months, rather than days. Others, like the Islamic calendar, do not use leap months or days. Other calendars simply synchronize with the Gregorian calendar for easier conversion. The Iranian calendar has a leap day calculated every 33 years, although sometimes it’s 29 or 37 years. The Iranian system is more complicated, but also more accurate to the vernal equinox year.
What does all of this really mean? It means that leap years are the only years where it is socially acceptable for women to ask men to marry them, of course! What else, besides breaking stifling social traditions with the implementation of silly ones, could come of a leap year? But men, don’t worry. A woman who is planning on asking a man to merry her is expected to wear either breeches or a scarlet petticoat, that way you’ll see them coming. You also have the option of saying no, but you are expected to pay a fine or buy the gal a dress.