Leap Year 2016: Why does February have 29 days every four years? Frogs are associated with leap years. This is a leaping frog   Phot...

Leap Year 2016: Why does February have 29 days every four years?

Frogs are associated with leap years. This is a leaping frog  Photo: Getty

Why do we have leap years?

A leap year, where an extra day is added to the end of February every four years, is down to the solar system's disparity with the Gregorian calendar.

A complete orbit of the earth around the sun takes exactly 365.2422 days to complete, but the Gregorian calendar uses 365 days.

So leap seconds - and leap years - are added as means of keeping our clocks (and calendars) in sync with the Earth and its seasons.

Why does the extra day fall in February?

All the other months in the Julian calendar have 30 or 31 days, but February lost out to the ego of Roman Emperor Caesar Augustus.

Under his predecessor Julius Caesar, February had 30 days and the month named after him - July - had 31. August had only 29 days.

When Caesar Augustus became Emperor he added two days to 'his' month to make August the same as July.

So February lost out to August in the battle of the extra days.

Technically, a leap year isn't every four years

The year 2000 was a leap year, but the years 1700, 1800 and 1900 were not.

There's a leap year every year that is divisible by four, except for years that are both divisible by 100 and not divisible by 400.

The added rule about centuries (versus just every four years) was an additional fix to make up for the fact that an extra day every four years is too much of a correction.